feat(ui): unify star map and atlas into single implant/map chain (#844)

Per D-191, the atlas is the star map extended downward — not a separate
app. AtlasPanel now owns the full Reach → system → planet → heightmap
zoom hierarchy as a single HudGroups app (implant/map).

- Add REACH_MAP as Level 0 of AtlasPanel's zoom hierarchy; renumber the
  enum so higher index = deeper zoom
- Port hop-ring rendering (pan/zoom, system markers, hover/info, sector
  layout) from star_map.gd into AtlasPanel methods
- Change AtlasPanel.APP_PATH from "implant/map/atlas" to "implant/map"
- main.gd: KEY_M toggles unified atlas; KEY_A binding removed
- Symmetric nav: ORBITAL_DIAGRAM back goes to REACH_MAP (not
  SYSTEM_PICKER), matching the forward skip
- hud_groups.gd docstring documents the unified path and flags the
  legacy starchart path as kept-for-compat (retirement tracked in #852)

star_map.gd's HudGroups registration stays live but inert — no key
binding reaches it. Full retirement follows in #852 after a sprint of
soak on the unified panel.

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

client/scripts/autoloads/hud_groups.gd

@@ -11,17 +11,18 @@ extends Node
 ##
 ## Groups use hierarchical paths:
 ##   "gameplay"                 — HUD status, minimap, prompts, stance
-##   "implant/map/starchart"   — star map navigator
+##   "implant/map"             — unified atlas (reach map → system → planet → regional, D-191)
+##   "implant/map/starchart"   — legacy hop-ring view (registered by StarMapRenderer, kept for compat)
 ##   "implant/wiki/gttr"       — Drifter's Guide reader
 ##   "implant/journal"         — knowledge journal
 ##   "implant/economics"       — economics monitor (D-181, #824)
 ##
 ## Usage:
-##   HudGroups.register(self, "implant/map/starchart")
-##   HudGroups.open_app("implant/map/starchart")     # fullscreen by default
-##   HudGroups.open_app("implant/map/starchart", HudGroups.MODE_INSERT)
+##   HudGroups.register(self, "implant/map")
+##   HudGroups.open_app("implant/map")     # fullscreen by default
+##   HudGroups.open_app("implant/map", HudGroups.MODE_INSERT)
 ##   HudGroups.close_app()
-##   HudGroups.toggle_app("implant/map/starchart")
+##   HudGroups.toggle_app("implant/map")
 
 ## Emitted when an app opens, closes, or changes mode.
 ## mode is a HudGroups.Mode enum value.

client/scripts/main.gd

@@ -178,17 +178,14 @@ func _ready() -> void:
 func _unhandled_key_input(event: InputEvent) -> void:
 	if event.is_pressed() and not event.is_echo():
 		if event is InputEventKey and event.keycode == KEY_M:
-			if star_map:
-				star_map.toggle_visible()
-		elif event is InputEventKey and event.keycode == KEY_A:
-			# #834: A — toggle Atlas implant panel (FULLSCREEN, implant/map/atlas)
+			# #844: M — unified atlas (implant/map). Reach map → system → planet → regional.
 			if atlas_panel:
 				atlas_panel.toggle_visible()
 		elif event is InputEventKey and event.keycode == KEY_N:
 			# #824: N — toggle Economics Monitor implant panel (E is bound to interact).
 			# Gated on the atlas being inactive so the viewer's N → city-economics
 			# cross-link isn't shadowed by this global toggle (review #6).
-			if economics_panel and not HudGroups.is_app_active("implant/map/atlas"):
+			if economics_panel and not HudGroups.is_app_active("implant/map"):
 				economics_panel.toggle_visible()
 		elif event is InputEventKey and event.keycode == KEY_BRACKETLEFT:
 			# #824: [ — cycle economics panel system selector backward

client/ui/hud.tscn

@@ -15,9 +15,7 @@ grow_vertical = 2
 mouse_filter = 2
 script = ExtResource("1_hud")
 
-; #674: Star map — full-screen insert overlay, hidden until player activates (M key / insert UI).
-; Toggled via star_map.toggle_visible() from main.gd.
-; TODO: migrate to HudGroups.open_app("implant/map/starchart") per D-170.
+; #674: Star map — legacy hop-ring node, kept for backward compat. Superseded by AtlasPanel REACH_MAP level (#844).
 [node name="StarMap" parent="." instance=ExtResource("2_starmap")]
 visible = false
 

client/ui/implant/atlas_panel.gd

@@ -1,13 +1,14 @@
 class_name AtlasPanel
 extends Control
 
-## Atlas implant panel — 4-level navigation (#834, #835):
-## system picker → orbital diagram → body entry → regional viewer.
-## FULLSCREEN implant app (z=20) at implant/map/atlas per D-170.
+## Atlas implant panel — unified 5-level nav chain (#844, D-191):
+## reach map → system picker → orbital diagram → body entry → regional viewer.
+## FULLSCREEN implant app (z=20) at implant/map per D-170.
 ## Uses ImplantPanel component library (D-169). Data from star_map_data.json.
 ##
 ## Navigation:
-##   Level 0 SYSTEM_PICKER    — ◄ ► cycle systems, Enter to open orbital view
+##   Level 4 REACH_MAP        — hop-ring view of the Reach gate network, click system → orbital
+##   Level 0 SYSTEM_PICKER    — ◄ ► cycle systems alphabetically, Enter to open orbital view
 ##   Level 1 ORBITAL_DIAGRAM  — rendered via _draw(), click body → level 2, click station → mini panel
 ##   Level 2 BODY_ENTRY       — body info panel, Enter to open heightmap viewer, Esc back
 ##   Level 3 HEIGHTMAP_VIEWER — AtlasViewer with pan/zoom + markers + city data (#835), Esc back
@@ -17,9 +18,9 @@ extends Control
 ## + HudGroups.open_app("implant/economics") — D-191 cross-panel integration.
 signal economics_link_requested(system_id: String)
 
-enum Level { SYSTEM_PICKER = 0, ORBITAL_DIAGRAM = 1, BODY_ENTRY = 2, HEIGHTMAP_VIEWER = 3 }
+enum Level { REACH_MAP = 0, SYSTEM_PICKER = 1, ORBITAL_DIAGRAM = 2, BODY_ENTRY = 3, HEIGHTMAP_VIEWER = 4 }
 
-const APP_PATH := "implant/map/atlas"
+const APP_PATH := "implant/map"
 const STAR_MAP_DATA := "res://data/star_map_data.json"
 const PANEL_WIDTH: float = 320.0
 const PANEL_MARGIN: float = 16.0
@@ -47,8 +48,57 @@ 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")
 
+# ── REACH_MAP (hop-ring) constants ────────────────────────────────────────────
+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
+
 # ── Navigation state ──────────────────────────────────────────────────────────
-var _level: Level = Level.SYSTEM_PICKER
+var _level: Level = Level.REACH_MAP
 var _systems: Array = []  # Array[Dictionary] from star_map_data.json
 var _selected_idx: int = 0  # index into _systems
 var _selected_body: Dictionary = {}  # body dict at Level.BODY_ENTRY
@@ -72,6 +122,18 @@ var _station_panel = null  # ImplantPanel — station mini, shown in level 1 on
 var _screen_header: ImplantHeader = null  # D-169-composed title/hint row (top-left)
 var _viewer = null  # AtlasViewer — level 3 heightmap viewer (#835)
 
+# ── REACH_MAP state ───────────────────────────────────────────────────────────
+var _reach_positions: Dictionary = {}  # system_id -> Vector2 (relative to map center)
+var _reach_node_lookup: Dictionary = {}  # system_id -> node dict
+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 — selected system details
+
 
 func _ready() -> void:
 	anchor_right = 1.0
@@ -93,7 +155,9 @@ func _ready() -> void:
 	_build_body_panel()
 	_build_station_panel()
 	_build_heightmap_viewer()
-	_show_level(Level.SYSTEM_PICKER)
+	_build_reach_info_panel()
+	_compute_reach_layout()
+	_show_level(Level.REACH_MAP)
 
 
 func _process(_delta: float) -> void:
@@ -104,7 +168,7 @@ func _process(_delta: float) -> void:
 		_dirty = false
 
 
-## Toggle atlas panel. Called from main.gd on KEY_A.
+## Toggle atlas panel. Called from main.gd on KEY_M.
 func toggle_visible() -> void:
 	HudGroups.toggle_app(APP_PATH, HudGroups.Mode.FULLSCREEN)
 
@@ -150,6 +214,8 @@ func _load_system_list() -> void:
 			var nb: String = b.get("proper_name", b.get("system_id", ""))
 			return na < nb
 	)
+	for node: Dictionary in _systems:
+		_reach_node_lookup[node.get("system_id", "")] = node
 
 
 func _current_system() -> Dictionary:
@@ -287,6 +353,8 @@ func _compute_body_positions() -> void:
 
 func _draw() -> void:
 	match _level:
+		Level.REACH_MAP:
+			_draw_reach()
 		Level.SYSTEM_PICKER:
 			_draw_picker_bg()
 		Level.ORBITAL_DIAGRAM:
@@ -343,9 +411,12 @@ func _refresh_screen_header() -> void:
 	var title: String = ""
 	var hint: String = ""
 	match _level:
+		Level.REACH_MAP:
+			title = "THE REACH — NAVIGATOR"
+			hint = "Concord Assembly Gate Network  ·  click system · enter open orbital · esc close"
 		Level.SYSTEM_PICKER:
 			title = "ATLAS — SYSTEM SELECTION"
-			hint = "select a system · ◄ ► cycle · enter open orbital view · esc close"
+			hint = "select a system · ◄ ► cycle · enter open orbital view · esc back"
 		Level.ORBITAL_DIAGRAM:
 			var sys: Dictionary = _current_system()
 			var sys_name: String = str(sys.get("proper_name", sys.get("system_id", "—")))
@@ -476,6 +547,8 @@ func _draw_stations() -> void:
 func _gui_input(event: InputEvent) -> void:
 	if event is InputEventKey and (event as InputEventKey).pressed and not event.is_echo():
 		_handle_key(event as InputEventKey)
+	elif _level == Level.REACH_MAP:
+		_handle_reach_input(event)
 	elif _level == Level.ORBITAL_DIAGRAM:
 		if event is InputEventMouseButton and (event as InputEventMouseButton).pressed:
 			_handle_orbital_click((event as InputEventMouseButton).position)
@@ -499,7 +572,9 @@ func _handle_key(event: InputEventKey) -> void:
 			if _level == Level.SYSTEM_PICKER:
 				_navigate_system(1)
 		KEY_ENTER, KEY_KP_ENTER:
-			if _level == Level.SYSTEM_PICKER:
+			if _level == Level.REACH_MAP:
+				_reach_enter_selected()
+			elif _level == Level.SYSTEM_PICKER:
 				_enter_orbital_diagram()
 			elif _level == Level.BODY_ENTRY:
 				_open_heightmap_viewer()
@@ -507,10 +582,12 @@ func _handle_key(event: InputEventKey) -> void:
 
 func _navigate_back() -> void:
 	match _level:
-		Level.SYSTEM_PICKER:
+		Level.REACH_MAP:
 			HudGroups.close_app()
+		Level.SYSTEM_PICKER:
+			_show_level(Level.REACH_MAP)
 		Level.ORBITAL_DIAGRAM:
-			_show_level(Level.SYSTEM_PICKER)
+			_show_level(Level.REACH_MAP)
 		Level.BODY_ENTRY:
 			_show_level(Level.ORBITAL_DIAGRAM)
 		Level.HEIGHTMAP_VIEWER:
@@ -601,6 +678,8 @@ func _show_level(level: Level) -> void:
 		_station_panel.visible = false
 	if _viewer:
 		_viewer.visible = (level == Level.HEIGHTMAP_VIEWER)
+	if _reach_info_panel:
+		_reach_info_panel.visible = (level == Level.REACH_MAP and _reach_selected != "")
 
 	_refresh_screen_header()
 	queue_redraw()
@@ -788,3 +867,386 @@ func _format_pop(pop: int) -> String:
 		result = s[i] + result
 		count += 1
 	return result
+
+
+# =============================================================================
+# REACH_MAP — hop-ring view (D-191: Reach map is Level 0 of the atlas hierarchy)
+# =============================================================================
+
+
+func _build_reach_info_panel() -> 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
+
+
+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
+
+
+# =============================================================================
+# REACH_MAP drawing
+# =============================================================================
+
+
+func _draw_reach() -> 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)
+
+	# Position info panel in top-right corner
+	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)
+
+
+# =============================================================================
+# REACH_MAP input
+# =============================================================================
+
+
+func _handle_reach_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
+	var idx := _reach_system_index(_reach_selected)
+	if idx >= 0:
+		_selected_idx = idx
+		_enter_orbital_diagram()