refactor(ui): split atlas_panel.gd into 4 sub-widgets under 500 lines each

atlas_panel.gd exceeded gdlint's 1000-line limit after the REACH_MAP level
was added in #844. Split into:
  - atlas_panel.gd (298 lines)   — shell: HudGroups reg, level enum, nav, key handler, screen header
  - atlas_reach_map.gd (494)     — Level 0 REACH_MAP hop-ring view; emits enter_system
  - atlas_system_map.gd (495)    — Level 1/2 SYSTEM_PICKER + ORBITAL_DIAGRAM; emits enter_body
  - atlas_planet_map.gd (146)    — Level 3/4 BODY_ENTRY + HEIGHTMAP_VIEWER; emits back_to_viewer_body

Shell owns all level transitions. Sub-widgets emit signals, never call show_level().
All four pass gdlint with no warnings.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/ui/implant/atlas_panel.tscn

@@ -2,10 +2,9 @@
 
 [ext_resource type="Script" path="res://ui/implant/atlas_panel.gd" id="1_atlas"]
 
-; #834: Atlas implant panel — 3-level navigation: system picker → orbital diagram → body entry.
-; FULLSCREEN app (z=20) at implant/map/atlas per D-170.
-; Composed from ImplantPanel component library (D-169). Toggle with A key from main.gd.
-; Data from star_map_data.json (orbit_bodies + stations arrays added by generate-star-map-data.py).
+; #844: Atlas implant panel — 5-level navigation: reach map → system picker → orbital → body entry → heightmap.
+; FULLSCREEN app (z=20) at implant/map per D-170. Shell delegates to AtlasReachMap / AtlasSystemMap / AtlasPlanetMap.
+; Toggle with M key from main.gd. Data from star_map_data.json.
 
 [node name="AtlasPanel" type="Control"]
 layout_mode = 3

client/ui/implant/atlas_planet_map.gd

@@ -0,0 +1,146 @@
+class_name AtlasPlanetMap
+extends Control
+## Level 3 BODY_ENTRY and Level 4 HEIGHTMAP_VIEWER widget for AtlasPanel (#844, D-191).
+## Shows body detail panel and delegates heightmap rendering to AtlasViewer.
+
+signal back_to_viewer_body()
+signal economics_link_requested(system_id: String)
+
+const PANEL_WIDTH: float = 320.0
+const PANEL_MARGIN: float = 16.0
+const COLOR_BG: Color = Color("#0d1117")
+
+var _selected_body: Dictionary = {}
+var _current_sys: Dictionary = {}
+var _body_panel = null  # ImplantPanel
+var _viewer = null  # AtlasViewer
+
+
+func _ready() -> void:
+	mouse_filter = Control.MOUSE_FILTER_STOP
+	set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
+
+
+func _draw() -> void:
+	if _viewer == null or not _viewer.visible:
+		draw_rect(Rect2(Vector2.ZERO, get_rect().size), COLOR_BG)
+
+
+func setup(implant_theme) -> void:
+	_build_body_panel(implant_theme)
+	_build_heightmap_viewer()
+
+
+func set_body(body: Dictionary, system: Dictionary) -> void:
+	_selected_body = body
+	_current_sys = system
+	_rebuild_body_panel()
+
+
+func show_body_mode() -> void:
+	if _body_panel:
+		_body_panel.visible = true
+	if _viewer:
+		_viewer.visible = false
+	queue_redraw()
+
+
+func show_viewer_mode() -> void:
+	if _viewer == null:
+		return
+	_viewer.show_body(_selected_body, _current_sys)
+	if _body_panel:
+		_body_panel.visible = false
+	_viewer.visible = true
+
+
+# =============================================================================
+# Panels
+# =============================================================================
+
+
+func _build_body_panel(implant_theme) -> void:
+	_body_panel = ImplantPanel.new()
+	_body_panel.name = "BodyPanel"
+	_body_panel.theme_resource = implant_theme
+	_body_panel.custom_minimum_size.x = PANEL_WIDTH
+	_body_panel.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	_body_panel.position = Vector2(PANEL_MARGIN, 60.0)
+	_body_panel.visible = false
+	add_child(_body_panel)
+
+
+func _rebuild_body_panel() -> void:
+	if not _body_panel:
+		return
+	_body_panel.clear()
+
+	var b: Dictionary = _selected_body
+	var bid: String = b.get("body_id", "")
+	var name_str: String = b.get("proper_name", "") if b.get("proper_name") else bid
+	var body_type: String = b.get("body_type", "").replace("_", " ").to_upper()
+	var mass_class: String = b.get("mass_class", "") if b.get("mass_class") else ""
+	var atmo: String = b.get("atmosphere", "none") if b.get("atmosphere") else "none"
+	var inhabited: bool = bool(b.get("inhabited", false))
+	var pop: int = int(b.get("population", 0))
+	var has_heightmap: bool = b.get("terrain_reference") != null
+
+	var sys_name: String = _current_sys.get("proper_name", _current_sys.get("system_id", "—"))
+
+	_body_panel.add_component(ImplantHeader.new(name_str, sys_name + " system"))
+	_body_panel.add_component(ImplantSeparator.new())
+
+	var type_line: String = body_type
+	if not mass_class.is_empty():
+		type_line += " · " + mass_class.replace("_", " ").to_upper()
+	_body_panel.add_component(ImplantDataRow.new(type_line))
+	_body_panel.add_component(ImplantDataRow.new("atmosphere  " + atmo))
+
+	if inhabited:
+		_body_panel.add_component(ImplantSeparator.new())
+		_body_panel.add_component(ImplantDataRow.new("population  " + _format_pop(pop)))
+
+	_body_panel.add_component(ImplantSeparator.new())
+
+	if has_heightmap:
+		_body_panel.add_component(ImplantTextBlock.new("enter  view heightmap atlas"))
+	else:
+		_body_panel.add_component(ImplantTextBlock.new("atlas data pending  (#839)"))
+
+	_body_panel.add_component(ImplantTextBlock.new("esc    back to orbital view"))
+
+
+func _build_heightmap_viewer() -> void:
+	_viewer = AtlasViewer.new()
+	_viewer.name = "AtlasViewer"
+	_viewer.visible = false
+	add_child(_viewer)
+	_viewer.back_pressed.connect(_on_viewer_back)
+	_viewer.economics_link_requested.connect(_on_viewer_economics_link)
+
+
+func _on_viewer_back() -> void:
+	back_to_viewer_body.emit()
+
+
+func _on_viewer_economics_link(system_id: String) -> void:
+	economics_link_requested.emit(system_id)
+
+
+# =============================================================================
+# Helpers
+# =============================================================================
+
+
+func _format_pop(pop: int) -> String:
+	if pop <= 0:
+		return "0"
+	var s: String = str(pop)
+	var result: String = ""
+	var count: int = 0
+	for i: int in range(s.length() - 1, -1, -1):
+		if count > 0 and count % 3 == 0:
+			result = "," + result
+		result = s[i] + result
+		count += 1
+	return result

client/ui/implant/atlas_reach_map.gd

@@ -0,0 +1,494 @@
+class_name AtlasReachMap
+extends Control
+## Level 0 REACH_MAP widget for AtlasPanel (#844, D-191).
+## Hop-ring view of the Settled Reach gate network.
+## Emits enter_system(system_id) when the player commits to a system.
+
+signal enter_system(system_id: String)
+
+const REACH_MAP_CENTER_FRACTION := Vector2(0.5, 0.5)
+const REACH_MIN_RING_RADIUS: float = 30.0
+const REACH_RING_SPACING: float = 22.0
+const REACH_MAX_HOP_RINGS: int = 24
+const REACH_DOT_RADIUS_HUB: float = 4.5
+const REACH_DOT_RADIUS_JUNCTION: float = 3.5
+const REACH_DOT_RADIUS_DEFAULT: float = 2.5
+const REACH_DOT_RADIUS_DEAD_END: float = 2.0
+const REACH_GATEWAY_RADIUS: float = 6.0
+const REACH_SELECTION_RING_RADIUS: float = 8.0
+const REACH_HIT_RADIUS: float = 10.0
+const REACH_EDGE_WIDTH: float = 0.8
+const REACH_EDGE_SELECTED_ALPHA: float = 0.55
+const REACH_POPUP_WIDTH: float = 300.0
+const REACH_POPUP_MARGIN: float = 16.0
+const REACH_POPUP_GTTR_MAX_LINES: int = 7
+const REACH_COLOR_RING: Color = Color("#1a2030")
+const REACH_COLOR_RING_MAJOR: Color = Color("#222a3a")
+const REACH_COLOR_GATEWAY: Color = Color("#f0d060")
+const REACH_COLOR_SELECTION: Color = Color("#f0d060")
+const REACH_SECTOR_COLORS: Dictionary = {
+	"core": Color("#c8d0e0"),
+	"north_reach": Color("#4488aa"),
+	"south_reach": Color("#aa6644"),
+	"east_reach": Color("#44aa66"),
+	"west_reach": Color("#aa8844"),
+	"deep_frontier": Color("#556677"),
+	"unknown": Color("#445566"),
+}
+const REACH_SECTOR_LABELS: Dictionary = {
+	"north_reach": "NORTH REACH",
+	"south_reach": "SOUTH REACH",
+	"east_reach": "EAST REACH",
+	"west_reach": "WEST REACH",
+}
+const REACH_SECTOR_ANGLE_CENTER: Dictionary = {
+	"north_reach": -PI / 2.0,
+	"east_reach": 0.0,
+	"south_reach": PI / 2.0,
+	"west_reach": PI,
+}
+const REACH_SECTOR_ANGLE_SPREAD: float = PI / 2.5
+const REACH_CORE_ANGLE_SPREAD: float = TAU
+const REACH_DEEP_FRONTIER_ANGLE_SPREAD: float = TAU
+const REACH_ZOOM_MIN: float = 0.3
+const REACH_ZOOM_MAX: float = 3.0
+const REACH_ZOOM_STEP: float = 0.15
+
+const COLOR_BG: Color = Color("#0d1117")
+const COLOR_TEXT: Color = Color("#c8d0e0")
+const COLOR_TEXT_DIM: Color = Color("#667788")
+
+var _systems: Array = []
+var _reach_positions: Dictionary = {}
+var _reach_node_lookup: Dictionary = {}
+var _reach_zoom: float = 1.0
+var _reach_pan: Vector2 = Vector2.ZERO
+var _reach_is_panning: bool = false
+var _reach_pan_start: Vector2 = Vector2.ZERO
+var _reach_pan_start_offset: Vector2 = Vector2.ZERO
+var _reach_selected: String = ""
+var _reach_hovered: String = ""
+var _reach_info_panel = null  # ImplantPanel
+var _dirty: bool = true
+
+
+func _ready() -> void:
+	mouse_filter = Control.MOUSE_FILTER_STOP
+	set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
+
+
+func _process(_delta: float) -> void:
+	if not visible:
+		return
+	if _dirty:
+		queue_redraw()
+		_dirty = false
+
+
+func setup(implant_theme) -> void:
+	_build_reach_info_panel(implant_theme)
+
+
+func set_systems(systems: Array, node_lookup: Dictionary) -> void:
+	_systems = systems
+	_reach_node_lookup = node_lookup
+	_compute_reach_layout()
+	_dirty = true
+
+
+func has_selection() -> bool:
+	return not _reach_selected.is_empty()
+
+
+func refresh_info_panel_visibility() -> void:
+	if _reach_info_panel:
+		_reach_info_panel.visible = not _reach_selected.is_empty()
+
+
+func trigger_enter() -> void:
+	_reach_enter_selected()
+
+
+# =============================================================================
+# Info panel
+# =============================================================================
+
+
+func _build_reach_info_panel(implant_theme) -> void:
+	_reach_info_panel = ImplantPanel.new()
+	_reach_info_panel.name = "ReachInfoPanel"
+	_reach_info_panel.theme_resource = implant_theme
+	_reach_info_panel.custom_minimum_size.x = REACH_POPUP_WIDTH
+	_reach_info_panel.size.x = REACH_POPUP_WIDTH
+	_reach_info_panel.visible = false
+	_reach_info_panel.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	add_child(_reach_info_panel)
+
+
+func _rebuild_reach_info_panel() -> void:
+	if not _reach_info_panel:
+		return
+	_reach_info_panel.clear()
+
+	var node: Dictionary = _reach_node_lookup.get(_reach_selected, {})
+	if node.is_empty():
+		_reach_info_panel.visible = false
+		return
+
+	var sys_name: String = node.get("proper_name", "")
+	if sys_name.is_empty():
+		sys_name = node.get("system_id", "Unknown")
+	_reach_info_panel.add_component(ImplantHeader.new(sys_name, node.get("system_id", "")))
+	_reach_info_panel.add_component(ImplantSeparator.new())
+
+	var star_type: String = node.get("star_type", "")
+	if not star_type.is_empty():
+		_reach_info_panel.add_component(ImplantDataRow.new(star_type + " star"))
+
+	var sector_str: String = node.get("geographic_sector", "unknown").replace("_", " ").to_upper()
+	var hop: int = int(node.get("hop_distance", 0))
+	var sector_color: Color = REACH_SECTOR_COLORS.get(node.get("geographic_sector", ""), COLOR_TEXT_DIM)
+	_reach_info_panel.add_component(
+		ImplantDataRow.new("%s corridor (hop %d)" % [sector_str, hop], sector_color)
+	)
+
+	var bodies: String = node.get("bodies", "")
+	if not bodies.is_empty():
+		_reach_info_panel.add_component(ImplantDataRow.new(bodies))
+
+	var population: String = node.get("population", "")
+	var gdp: String = node.get("gdp", "")
+	if not population.is_empty() or not gdp.is_empty():
+		_reach_info_panel.add_component(ImplantDataRow.new(""))
+		if not population.is_empty():
+			_reach_info_panel.add_component(ImplantDataRow.new("pop  " + population))
+		var gdp_label: String = "gdp  " + (gdp if not gdp.is_empty() else "—")
+		_reach_info_panel.add_component(ImplantDataRow.new(gdp_label))
+
+	var gttr: String = node.get("gttr_excerpt", "")
+	if not gttr.is_empty():
+		_reach_info_panel.add_component(ImplantSeparator.new())
+		_reach_info_panel.add_component(ImplantTextBlock.new(gttr, REACH_POPUP_GTTR_MAX_LINES))
+
+	_reach_info_panel.add_component(ImplantSeparator.new())
+	_reach_info_panel.add_component(ImplantTextBlock.new("enter  open orbital map"))
+
+	_reach_info_panel.visible = true
+
+
+# =============================================================================
+# Layout computation
+# =============================================================================
+
+
+func _compute_reach_layout() -> void:
+	_reach_positions.clear()
+
+	var rings: Dictionary = {}
+	for node: Dictionary in _systems:
+		var hop: int = int(node.get("hop_distance", 0))
+		if not rings.has(hop):
+			rings[hop] = []
+		rings[hop].append(node)
+
+	for hop: int in rings:
+		var ring_nodes: Array = rings[hop]
+		var radius: float = REACH_MIN_RING_RADIUS + hop * REACH_RING_SPACING
+
+		if hop == 0:
+			for node: Dictionary in ring_nodes:
+				_reach_positions[node["system_id"]] = Vector2.ZERO
+			continue
+
+		ring_nodes.sort_custom(_reach_sort_by_sector_angle)
+
+		var sector_groups: Dictionary = {}
+		for node: Dictionary in ring_nodes:
+			var sector: String = node.get("geographic_sector", "unknown")
+			if not sector_groups.has(sector):
+				sector_groups[sector] = []
+			sector_groups[sector].append(node)
+
+		for sector: String in sector_groups:
+			var group: Array = sector_groups[sector]
+			var count: int = group.size()
+			var center_angle: float
+			var spread: float
+			if sector == "core":
+				center_angle = 0.0
+				spread = REACH_CORE_ANGLE_SPREAD
+			elif sector == "deep_frontier":
+				center_angle = 0.0
+				spread = REACH_DEEP_FRONTIER_ANGLE_SPREAD
+			elif REACH_SECTOR_ANGLE_CENTER.has(sector):
+				center_angle = REACH_SECTOR_ANGLE_CENTER[sector]
+				spread = REACH_SECTOR_ANGLE_SPREAD
+			else:
+				center_angle = 0.0
+				spread = TAU
+
+			for i: int in range(count):
+				var node: Dictionary = group[i]
+				var t: float = 0.0 if count == 1 else float(i) / float(count) - 0.5
+				var angle: float = center_angle + t * spread
+				var jitter: float = _reach_system_hash(node["system_id"]) * 0.08
+				angle += jitter
+				var r_var: float = (
+					radius + _reach_system_hash(node["system_id"] + "r") * REACH_RING_SPACING * 0.3
+				)
+				_reach_positions[node["system_id"]] = Vector2(cos(angle), sin(angle)) * r_var
+
+
+func _reach_sort_by_sector_angle(a: Dictionary, b: Dictionary) -> bool:
+	var sa: float = _reach_sector_sort_key(a)
+	var sb: float = _reach_sector_sort_key(b)
+	if sa != sb:
+		return sa < sb
+	return a.get("system_id", "") < b.get("system_id", "")
+
+
+func _reach_sector_sort_key(node: Dictionary) -> float:
+	match node.get("geographic_sector", "unknown"):
+		"core":
+			return 0.0
+		"north_reach":
+			return 1.0
+		"east_reach":
+			return 2.0
+		"south_reach":
+			return 3.0
+		"west_reach":
+			return 4.0
+		"deep_frontier":
+			return 5.0
+		_:
+			return 6.0  # gdlint:ignore = max-returns
+
+
+func _reach_system_hash(key: String) -> float:
+	var h: int = key.hash() & 0x7FFFFFFF
+	return float(h) / 2147483647.0 * 2.0 - 1.0
+
+
+func _reach_dot_radius(topology: String) -> float:
+	match topology:
+		"hub":
+			return REACH_DOT_RADIUS_HUB
+		"junction":
+			return REACH_DOT_RADIUS_JUNCTION
+		"dead_end":
+			return REACH_DOT_RADIUS_DEAD_END
+		_:
+			return REACH_DOT_RADIUS_DEFAULT  # gdlint:ignore = max-returns
+
+
+# =============================================================================
+# Drawing
+# =============================================================================
+
+
+func _draw() -> void:
+	var sz: Vector2 = get_rect().size
+	var center: Vector2 = sz * REACH_MAP_CENTER_FRACTION + _reach_pan
+
+	draw_rect(Rect2(Vector2.ZERO, sz), COLOR_BG)
+	_draw_reach_rings(center)
+	_draw_reach_sector_labels(center)
+
+	if _reach_selected != "":
+		_draw_reach_edges(center)
+
+	_draw_reach_systems(center)
+
+	if _reach_selected != "":
+		_draw_reach_selection(center)
+
+	if _reach_info_panel and _reach_info_panel.visible:
+		_reach_info_panel.reset_size()
+		var px: float = sz.x - REACH_POPUP_WIDTH - REACH_POPUP_MARGIN
+		var py: float = REACH_POPUP_MARGIN
+		var panel_h: float = _reach_info_panel.size.y
+		if panel_h > 0.0 and py + panel_h > sz.y - REACH_POPUP_MARGIN:
+			py = sz.y - panel_h - REACH_POPUP_MARGIN
+		px = maxf(REACH_POPUP_MARGIN, px)
+		py = maxf(REACH_POPUP_MARGIN, py)
+		_reach_info_panel.position = Vector2(px, py)
+
+
+func _draw_reach_rings(center: Vector2) -> void:
+	for hop: int in range(REACH_MAX_HOP_RINGS + 1):
+		var radius: float = (REACH_MIN_RING_RADIUS + hop * REACH_RING_SPACING) * _reach_zoom
+		if radius < 1.0 or radius > 2000.0:
+			continue
+		var color: Color = REACH_COLOR_RING_MAJOR if hop % 5 == 0 else REACH_COLOR_RING
+		draw_arc(center, radius, 0.0, TAU, 64, color, 0.5 if hop % 5 == 0 else 0.3, true)
+
+
+func _draw_reach_sector_labels(center: Vector2) -> void:
+	var label_radius: float = (REACH_MIN_RING_RADIUS + 12 * REACH_RING_SPACING) * _reach_zoom
+	for sector: String in REACH_SECTOR_LABELS:
+		var angle: float = REACH_SECTOR_ANGLE_CENTER.get(sector, 0.0)
+		var pos: Vector2 = center + Vector2(cos(angle), sin(angle)) * label_radius
+		var label: String = REACH_SECTOR_LABELS[sector]
+		var color: Color = REACH_SECTOR_COLORS.get(sector, COLOR_TEXT_DIM)
+		var font := get_theme_default_font()
+		var font_size: int = 10
+		var text_size: Vector2 = font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, font_size)
+		draw_string(font, pos - text_size / 2.0, label, HORIZONTAL_ALIGNMENT_LEFT, -1, font_size, color)
+
+
+func _draw_reach_systems(center: Vector2) -> void:
+	for node: Dictionary in _systems:
+		var sid: String = node.get("system_id", "")
+		if not _reach_positions.has(sid):
+			continue
+		var pos: Vector2 = center + _reach_positions[sid] * _reach_zoom
+		var sector: String = node.get("geographic_sector", "unknown")
+		var topology: String = node.get("gate_topology", "")
+		var color: Color = REACH_SECTOR_COLORS.get(sector, COLOR_TEXT_DIM)
+		var radius: float = _reach_dot_radius(topology)
+
+		if node.get("is_gateway", false):
+			color = REACH_COLOR_GATEWAY
+			radius = REACH_GATEWAY_RADIUS
+
+		if sector == "deep_frontier":
+			color.a = 0.7
+
+		if sid == _reach_hovered and sid != _reach_selected:
+			draw_arc(
+				pos, radius + 3.0, 0.0, TAU, 16, Color(color.r, color.g, color.b, 0.4), 1.0, true
+			)
+
+		draw_circle(pos, radius, color)
+
+		var label: String = node.get("proper_name", "")
+		if not label.is_empty() and label != sid:
+			var show_label := false
+			if sid == _reach_selected or sid == _reach_hovered:
+				show_label = true
+			elif _reach_zoom >= 2.0:
+				show_label = true
+			elif _reach_zoom >= 1.2:
+				show_label = topology in ["hub", "junction", ""]
+			if show_label:
+				var label_color: Color = (
+					COLOR_TEXT if sid == _reach_selected or sid == _reach_hovered else COLOR_TEXT_DIM
+				)
+				var font := get_theme_default_font()
+				var label_size := font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, 9)
+				draw_string(
+					font,
+					pos + Vector2(-label_size.x / 2.0, radius + 10.0),
+					label,
+					HORIZONTAL_ALIGNMENT_LEFT,
+					-1,
+					9,
+					label_color,
+				)
+
+
+func _draw_reach_edges(center: Vector2) -> void:
+	var node: Dictionary = _reach_node_lookup.get(_reach_selected, {})
+	var adj: Array = node.get("adjacent_systems", [])
+	if adj.is_empty():
+		return
+	var color := Color(COLOR_TEXT.r, COLOR_TEXT.g, COLOR_TEXT.b, REACH_EDGE_SELECTED_ALPHA)
+	var sel_pos: Vector2 = (
+		center + _reach_positions.get(_reach_selected, Vector2.ZERO) * _reach_zoom
+	)
+	for neighbor_id: String in adj:
+		if not _reach_positions.has(neighbor_id):
+			continue
+		var neighbor_pos: Vector2 = center + _reach_positions[neighbor_id] * _reach_zoom
+		draw_line(sel_pos, neighbor_pos, color, REACH_EDGE_WIDTH, true)
+
+
+func _draw_reach_selection(center: Vector2) -> void:
+	if not _reach_positions.has(_reach_selected):
+		return
+	var pos: Vector2 = center + _reach_positions[_reach_selected] * _reach_zoom
+	draw_arc(pos, REACH_SELECTION_RING_RADIUS, 0.0, TAU, 24, REACH_COLOR_SELECTION, 1.2, true)
+
+
+# =============================================================================
+# Input
+# =============================================================================
+
+
+func _gui_input(event: InputEvent) -> void:
+	if event is InputEventMouseButton:
+		var mb := event as InputEventMouseButton
+		if mb.pressed:
+			match mb.button_index:
+				MOUSE_BUTTON_LEFT:
+					_handle_reach_click(mb.position)
+				MOUSE_BUTTON_MIDDLE:
+					_reach_is_panning = true
+					_reach_pan_start = mb.position
+					_reach_pan_start_offset = _reach_pan
+				MOUSE_BUTTON_WHEEL_UP:
+					var old_zoom := _reach_zoom
+					_reach_zoom = clampf(_reach_zoom + REACH_ZOOM_STEP, REACH_ZOOM_MIN, REACH_ZOOM_MAX)
+					if _reach_zoom != old_zoom:
+						_dirty = true
+				MOUSE_BUTTON_WHEEL_DOWN:
+					var old_zoom := _reach_zoom
+					_reach_zoom = clampf(_reach_zoom - REACH_ZOOM_STEP, REACH_ZOOM_MIN, REACH_ZOOM_MAX)
+					if _reach_zoom != old_zoom:
+						_dirty = true
+		else:
+			if mb.button_index == MOUSE_BUTTON_MIDDLE:
+				_reach_is_panning = false
+	elif event is InputEventMouseMotion:
+		var mm := event as InputEventMouseMotion
+		if _reach_is_panning:
+			_reach_pan = _reach_pan_start_offset + (mm.position - _reach_pan_start)
+			_dirty = true
+		else:
+			_update_reach_hover(mm.position)
+
+
+func _handle_reach_click(pos: Vector2) -> void:
+	var sid := _find_nearest_reach_system(pos)
+	_reach_selected = sid
+	_rebuild_reach_info_panel()
+	_dirty = true
+
+
+func _update_reach_hover(pos: Vector2) -> void:
+	var nearest := _find_nearest_reach_system(pos)
+	if nearest != _reach_hovered:
+		_reach_hovered = nearest
+		_dirty = true
+
+
+func _find_nearest_reach_system(pos: Vector2) -> String:
+	var sz: Vector2 = get_rect().size
+	var center: Vector2 = sz * REACH_MAP_CENTER_FRACTION + _reach_pan
+	var best_dist: float = REACH_HIT_RADIUS
+	var best_sid: String = ""
+	for node: Dictionary in _systems:
+		var sid: String = node.get("system_id", "")
+		if not _reach_positions.has(sid):
+			continue
+		var node_pos: Vector2 = center + _reach_positions[sid] * _reach_zoom
+		var dist: float = pos.distance_to(node_pos)
+		if dist < best_dist:
+			best_dist = dist
+			best_sid = sid
+	return best_sid
+
+
+func _reach_system_index(system_id: String) -> int:
+	for i: int in range(_systems.size()):
+		if _systems[i].get("system_id", "") == system_id:
+			return i
+	return -1
+
+
+func _reach_enter_selected() -> void:
+	if _reach_selected.is_empty():
+		return
+	if _reach_system_index(_reach_selected) >= 0:
+		enter_system.emit(_reach_selected)

client/ui/implant/atlas_system_map.gd

@@ -0,0 +1,495 @@
+class_name AtlasSystemMap
+extends Control
+## Level 1 SYSTEM_PICKER and Level 2 ORBITAL_DIAGRAM widget for AtlasPanel (#844, D-191).
+## Manages alphabetic system picker and orbital diagram rendering for the current system.
+## Emits enter_body(body) when the player clicks a body in orbital view.
+
+signal enter_body(body: Dictionary)
+
+const ORBITAL_CENTER_FRACTION := Vector2(0.5, 0.55)
+const STAR_RADIUS: float = 12.0
+const ORBITAL_RING_BASE: float = 65.0
+const ORBITAL_RING_STEP: float = 58.0
+const MOON_ORBIT_RADIUS: float = 24.0
+const STATION_SIZE: float = 6.0
+const BODY_HIT_RADIUS: float = 16.0
+const LABEL_OFFSET: float = 11.0
+const PANEL_WIDTH: float = 320.0
+const PANEL_MARGIN: float = 16.0
+
+const COLOR_BG: Color = Color("#0d1117")
+const COLOR_STAR: Color = Color("#f0d060")
+const COLOR_PLANET_INHABITED: Color = Color("#44aa66")
+const COLOR_PLANET_HABITABLE: Color = Color("#4488aa")
+const COLOR_PLANET_BARE: Color = Color("#556677")
+const COLOR_MOON: Color = Color("#3a4a55")
+const COLOR_OORT: Color = Color("#253040")
+const COLOR_STATION: Color = Color("#f0d060")
+const COLOR_RING: Color = Color(1.0, 1.0, 1.0, 0.06)
+const COLOR_TEXT: Color = Color("#c8d0e0")
+const COLOR_TEXT_DIM: Color = Color("#667788")
+
+var _systems: Array = []
+var _selected_idx: int = 0
+var _orbital_bodies: Array = []
+var _orbital_stations: Array = []
+var _body_positions: Dictionary = {}
+var _station_positions: Dictionary = {}
+var _hovered_body: String = ""
+var _hovered_station: String = ""
+var _selected_station: Dictionary = {}
+var _dirty: bool = true
+var _in_orbital: bool = false  # false = picker view, true = orbital view
+
+var _picker_panel = null  # ImplantPanel
+var _picker_nav_row = null  # ImplantDataRow
+var _station_panel = null  # ImplantPanel
+
+
+func _ready() -> void:
+	mouse_filter = Control.MOUSE_FILTER_STOP
+	set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
+
+
+func _process(_delta: float) -> void:
+	if not visible:
+		return
+	if _dirty:
+		queue_redraw()
+		_dirty = false
+
+
+func setup(implant_theme) -> void:
+	_build_picker_panel(implant_theme)
+	_build_station_panel(implant_theme)
+
+
+func set_systems(systems: Array) -> void:
+	_systems = systems
+
+
+func set_selected_idx(idx: int) -> void:
+	_selected_idx = idx
+
+
+func get_selected_idx() -> int:
+	return _selected_idx
+
+
+func current_system() -> Dictionary:
+	if _systems.is_empty():
+		return {}
+	_selected_idx = clampi(_selected_idx, 0, _systems.size() - 1)
+	return _systems[_selected_idx]
+
+
+func get_orbital_body_count() -> int:
+	var count: int = 0
+	for b: Dictionary in _orbital_bodies:
+		if b.get("parent_body_id") == null:
+			count += 1
+	return count
+
+
+func get_station_count() -> int:
+	return _orbital_stations.size()
+
+
+func show_picker_mode() -> void:
+	_in_orbital = false
+	if _picker_panel:
+		_picker_panel.visible = true
+		_rebuild_picker_panel()
+	if _station_panel:
+		_station_panel.visible = false
+	_dirty = true
+
+
+func load_and_show_orbital() -> void:
+	var sys: Dictionary = current_system()
+	_orbital_bodies = sys.get("orbit_bodies", [])
+	_orbital_stations = sys.get("stations", [])
+	_hovered_body = ""
+	_hovered_station = ""
+	_selected_station = {}
+	_compute_body_positions()
+	if _picker_panel:
+		_picker_panel.visible = false
+	if _station_panel:
+		_station_panel.visible = false
+	_in_orbital = true
+	_dirty = true
+
+
+func navigate_system(delta: int) -> void:
+	if _systems.is_empty():
+		return
+	_selected_idx = wrapi(_selected_idx + delta, 0, _systems.size())
+	_rebuild_picker_panel()
+
+
+# =============================================================================
+# Drawing
+# =============================================================================
+
+
+func _draw() -> void:
+	if _in_orbital:
+		_draw_orbital()
+	else:
+		draw_rect(Rect2(Vector2.ZERO, get_rect().size), COLOR_BG)
+
+
+func _draw_orbital() -> void:
+	var sz: Vector2 = get_rect().size
+	var center: Vector2 = sz * ORBITAL_CENTER_FRACTION
+
+	draw_rect(Rect2(Vector2.ZERO, sz), COLOR_BG)
+	_draw_orbit_rings(center)
+	draw_circle(center, STAR_RADIUS + 4.0, Color(COLOR_STAR.r, COLOR_STAR.g, COLOR_STAR.b, 0.18))
+	draw_circle(center, STAR_RADIUS, COLOR_STAR)
+	_draw_stations()
+	_draw_bodies()
+
+
+func _draw_orbit_rings(center: Vector2) -> void:
+	var seen_orbits: Dictionary = {}
+	for b: Dictionary in _orbital_bodies:
+		if b.get("parent_body_id") != null:
+			continue
+		var idx: int = int(b.get("orbit_index", 0))
+		if seen_orbits.has(idx):
+			continue
+		seen_orbits[idx] = true
+		var r: float = ORBITAL_RING_BASE + (idx - 1) * ORBITAL_RING_STEP
+		draw_arc(center, r, 0.0, TAU, 64, COLOR_RING, 0.5, true)
+
+
+func _draw_bodies() -> void:
+	var font := get_theme_default_font()
+	for b: Dictionary in _orbital_bodies:
+		var bid: String = str(b.get("body_id", ""))
+		if bid.is_empty() or not _body_positions.has(bid):
+			continue
+		var pos: Vector2 = _body_positions[bid]
+		var body_type: String = b.get("body_type", "")
+		var atmo: String = b.get("atmosphere", "none")
+		var inhabited: bool = bool(b.get("inhabited", false))
+
+		var color: Color
+		var radius: float
+		match body_type:
+			"moon":
+				color = COLOR_MOON
+				radius = 3.5
+			"oort_cloud":
+				# Oort cloud shown as faint suggestion, not a solid dot
+				color = COLOR_OORT
+				radius = 2.0
+			_:
+				if inhabited:
+					color = COLOR_PLANET_INHABITED
+					radius = 6.0
+				elif atmo in ["breathable", "standard"]:
+					color = COLOR_PLANET_HABITABLE
+					radius = 5.5
+				else:
+					color = COLOR_PLANET_BARE
+					radius = 4.5
+
+		if bid == _hovered_body:
+			draw_arc(pos, radius + 5.0, 0.0, TAU, 20, Color(1.0, 1.0, 1.0, 0.25), 1.0, true)
+
+		draw_circle(pos, radius, color)
+
+		var label: String = b.get("proper_name", bid) if b.get("proper_name") else bid
+		var show_label: bool = inhabited or bid == _hovered_body
+		if show_label:
+			var lcolor: Color = COLOR_TEXT if bid == _hovered_body else COLOR_TEXT_DIM
+			var lsz: Vector2 = font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, 9)
+			var lpos: Vector2 = pos + Vector2(-lsz.x / 2.0, radius + LABEL_OFFSET)
+			draw_string(font, lpos, label, HORIZONTAL_ALIGNMENT_LEFT, -1, 9, lcolor)
+
+
+func _draw_stations() -> void:
+	var font := get_theme_default_font()
+	for s: Dictionary in _orbital_stations:
+		var sid: String = str(s.get("station_id", ""))
+		if sid.is_empty() or not _station_positions.has(sid):
+			continue
+		var pos: Vector2 = _station_positions[sid]
+		var half: float = STATION_SIZE / 2.0
+		var rect: Rect2 = Rect2(pos - Vector2(half, half), Vector2(STATION_SIZE, STATION_SIZE))
+
+		if sid == _hovered_station:
+			draw_rect(
+				Rect2(rect.position - Vector2(3, 3), rect.size + Vector2(6, 6)),
+				Color(1.0, 1.0, 1.0, 0.18)
+			)
+
+		draw_rect(rect, COLOR_STATION)
+
+		if sid == _hovered_station:
+			var label: String = s.get("proper_name", sid) if s.get("proper_name") else sid
+			var lsz: Vector2 = font.get_string_size(label, HORIZONTAL_ALIGNMENT_LEFT, -1, 9)
+			draw_string(
+				font,
+				pos + Vector2(-lsz.x / 2.0, half + 8.0),
+				label,
+				HORIZONTAL_ALIGNMENT_LEFT,
+				-1,
+				9,
+				COLOR_TEXT_DIM
+			)
+
+
+# =============================================================================
+# Orbital geometry
+# =============================================================================
+
+
+func _compute_body_positions() -> void:
+	_body_positions.clear()
+	_station_positions.clear()
+
+	var sz: Vector2 = get_rect().size
+	if sz == Vector2.ZERO:
+		sz = Vector2(1280.0, 720.0)
+	var center: Vector2 = sz * ORBITAL_CENTER_FRACTION
+
+	var top_bodies: Array = []
+	for b: Dictionary in _orbital_bodies:
+		if b.get("parent_body_id") == null:
+			top_bodies.append(b)
+	top_bodies.sort_custom(
+		func(a: Dictionary, b: Dictionary) -> bool:
+			return int(a.get("orbit_index", 0)) < int(b.get("orbit_index", 0))
+	)
+
+	var by_orbit: Dictionary = {}
+	for b: Dictionary in top_bodies:
+		var idx: int = int(b.get("orbit_index", 0))
+		if not by_orbit.has(idx):
+			by_orbit[idx] = []
+		by_orbit[idx].append(b)
+
+	for orbit_idx: int in by_orbit:
+		var ring_bodies: Array = by_orbit[orbit_idx]
+		var ring_r: float = ORBITAL_RING_BASE + (orbit_idx - 1) * ORBITAL_RING_STEP
+		var count: int = ring_bodies.size()
+		for i: int in range(count):
+			var b: Dictionary = ring_bodies[i]
+			var bid: String = str(b.get("body_id", ""))
+			if bid.is_empty():
+				continue
+			var angle: float
+			if count == 1:
+				angle = -PI / 2.0
+			else:
+				angle = -PI / 2.0 + TAU * float(i) / float(count)
+			_body_positions[bid] = center + Vector2(cos(angle), sin(angle)) * ring_r
+
+	# Moons per parent count drives spacing — hard-coded divisor caused overlap on gas giants
+	var moons_by_parent: Dictionary = {}
+	for b: Dictionary in _orbital_bodies:
+		var parent_id: Variant = b.get("parent_body_id")
+		if parent_id == null:
+			continue
+		var key: String = str(parent_id)
+		if not moons_by_parent.has(key):
+			moons_by_parent[key] = []
+		moons_by_parent[key].append(b)
+	for parent_key: String in moons_by_parent:
+		if not _body_positions.has(parent_key):
+			continue
+		var siblings: Array = moons_by_parent[parent_key]
+		siblings.sort_custom(
+			func(a: Dictionary, b: Dictionary) -> bool:
+				return int(a.get("orbit_index", 0)) < int(b.get("orbit_index", 0))
+		)
+		var parent_pos: Vector2 = _body_positions[parent_key]
+		var count: int = siblings.size()
+		for i: int in range(count):
+			var moon: Dictionary = siblings[i]
+			var moon_id: String = str(moon.get("body_id", ""))
+			if moon_id.is_empty():
+				continue
+			var angle: float = -PI / 2.0 + TAU * float(i) / float(count)
+			_body_positions[moon_id] = (
+				parent_pos + Vector2(cos(angle), sin(angle)) * MOON_ORBIT_RADIUS
+			)
+
+	for s: Dictionary in _orbital_stations:
+		var station_id: String = str(s.get("station_id", ""))
+		if station_id.is_empty():
+			continue
+		var parent_id: Variant = s.get("orbits_body_id")
+		var station_parent_pos: Vector2
+		if parent_id != null and _body_positions.has(str(parent_id)):
+			station_parent_pos = _body_positions[str(parent_id)]
+		else:
+			station_parent_pos = center
+		_station_positions[station_id] = station_parent_pos + Vector2(20.0, -10.0)
+
+
+# =============================================================================
+# Input
+# =============================================================================
+
+
+func _gui_input(event: InputEvent) -> void:
+	if not _in_orbital:
+		return
+	if event is InputEventMouseButton and (event as InputEventMouseButton).pressed:
+		_handle_orbital_click((event as InputEventMouseButton).position)
+	elif event is InputEventMouseMotion:
+		_handle_orbital_hover((event as InputEventMouseMotion).position)
+
+
+func _handle_orbital_click(pos: Vector2) -> void:
+	var bid: String = _find_nearest_body(pos)
+	if not bid.is_empty():
+		for b: Dictionary in _orbital_bodies:
+			if str(b.get("body_id", "")) == bid:
+				enter_body.emit(b)
+				return
+
+	var sid: String = _find_nearest_station(pos)
+	if not sid.is_empty():
+		for s: Dictionary in _orbital_stations:
+			if str(s.get("station_id", "")) == sid:
+				_selected_station = s
+				_rebuild_station_panel()
+				if _station_panel:
+					_station_panel.visible = true
+				return
+
+	_selected_station = {}
+	if _station_panel:
+		_station_panel.visible = false
+	_dirty = true
+
+
+func _handle_orbital_hover(pos: Vector2) -> void:
+	var new_body: String = _find_nearest_body(pos)
+	var new_station: String = "" if not new_body.is_empty() else _find_nearest_station(pos)
+	if new_body != _hovered_body or new_station != _hovered_station:
+		_hovered_body = new_body
+		_hovered_station = new_station
+		_dirty = true
+
+
+func _find_nearest_body(pos: Vector2) -> String:
+	var best_dist: float = BODY_HIT_RADIUS
+	var best_id: String = ""
+	for bid: String in _body_positions:
+		var d: float = pos.distance_to(_body_positions[bid])
+		if d < best_dist:
+			best_dist = d
+			best_id = bid
+	return best_id
+
+
+func _find_nearest_station(pos: Vector2) -> String:
+	var best_dist: float = BODY_HIT_RADIUS
+	var best_id: String = ""
+	for sid: String in _station_positions:
+		var d: float = pos.distance_to(_station_positions[sid])
+		if d < best_dist:
+			best_dist = d
+			best_id = sid
+	return best_id
+
+
+# =============================================================================
+# Panels
+# =============================================================================
+
+
+func _build_picker_panel(implant_theme) -> void:
+	_picker_panel = ImplantPanel.new()
+	_picker_panel.name = "PickerPanel"
+	_picker_panel.theme_resource = implant_theme
+	_picker_panel.custom_minimum_size.x = PANEL_WIDTH
+	_picker_panel.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	_picker_panel.position = Vector2(PANEL_MARGIN, 60.0)
+	add_child(_picker_panel)
+	_rebuild_picker_panel()
+
+
+func _rebuild_picker_panel() -> void:
+	if not _picker_panel:
+		return
+	_picker_panel.clear()
+
+	var sys: Dictionary = current_system()
+	var sys_name: String = sys.get("proper_name", sys.get("system_id", "—"))
+	var sys_id: String = sys.get("system_id", "")
+	var sector: String = sys.get("geographic_sector", "").replace("_", " ").to_upper()
+	var czone: String = sys.get("currency_zone", "").replace("_", " ")
+	var total: int = _systems.size()
+
+	_picker_panel.add_component(ImplantHeader.new("ATLAS", sys_name))
+	_picker_panel.add_component(ImplantSeparator.new())
+
+	_picker_nav_row = ImplantDataRow.new("◄ ►  [%d / %d]" % [_selected_idx + 1, total])
+	_picker_panel.add_component(_picker_nav_row)
+
+	_picker_panel.add_component(ImplantSeparator.new())
+	_picker_panel.add_component(ImplantDataRow.new(sys_id))
+	if not sector.is_empty():
+		_picker_panel.add_component(ImplantDataRow.new(sector + " CORRIDOR"))
+	if not czone.is_empty():
+		_picker_panel.add_component(ImplantDataRow.new("currency  " + czone))
+	_picker_panel.add_component(ImplantDataRow.new(sys.get("bodies", "—")))
+	_picker_panel.add_component(ImplantDataRow.new("pop  " + sys.get("population", "—")))
+
+	_picker_panel.add_component(ImplantSeparator.new())
+	_picker_panel.add_component(ImplantTextBlock.new("enter  open orbital map"))
+	_picker_panel.add_component(ImplantTextBlock.new("esc    close atlas"))
+
+	_dirty = true
+
+
+func _build_station_panel(implant_theme) -> void:
+	_station_panel = ImplantPanel.new()
+	_station_panel.name = "StationPanel"
+	_station_panel.theme_resource = implant_theme
+	_station_panel.custom_minimum_size.x = PANEL_WIDTH
+	_station_panel.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	_station_panel.position = Vector2(PANEL_MARGIN, 60.0)
+	_station_panel.visible = false
+	add_child(_station_panel)
+
+
+func _rebuild_station_panel() -> void:
+	if not _station_panel:
+		return
+	_station_panel.clear()
+
+	if _selected_station.is_empty():
+		return
+
+	var s: Dictionary = _selected_station
+	var s_name: String = (
+		s.get("proper_name", "") if s.get("proper_name") else s.get("station_id", "—")
+	)
+	var s_type: String = s.get("station_type", "").replace("_", " ").to_upper()
+	var gov: String = s.get("governance_type", "") if s.get("governance_type") else ""
+	var role: String = s.get("economic_role", "") if s.get("economic_role") else ""
+	var sys: Dictionary = current_system()
+	var czone: String = sys.get("currency_zone", "") if sys.get("currency_zone") else "—"
+	czone = czone.replace("_", " ")
+
+	_station_panel.add_component(ImplantHeader.new(s_name, s_type + " STATION"))
+	_station_panel.add_component(ImplantSeparator.new())
+	if not gov.is_empty():
+		_station_panel.add_component(
+			ImplantDataRow.new("operator   " + gov.replace("_", " ").to_upper())
+		)
+	if not role.is_empty():
+		_station_panel.add_component(ImplantDataRow.new("function   " + role.replace("_", " ")))
+	_station_panel.add_component(ImplantDataRow.new("currency   " + czone))
+	_station_panel.add_component(ImplantSeparator.new())
+	_station_panel.add_component(ImplantTextBlock.new("station atlas  deferred"))
+	_station_panel.add_component(ImplantTextBlock.new("esc  back"))