feat(ui): economics monitor insert panel with placeholder data (#824)

New implant panel at implant/economics: system selector, 6-commodity
price table with trend indicators, GDP strip. Composed from D-169
component library. Ring buffer caches last 20 ticks per system.
Snapshot routing wired through snapshot_handler → GameState →
snapshot_consumers → economics_panel. Placeholder prices shown
until server ships EconomySnapshot (#822).

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

client/scripts/autoloads/game_state.gd

@@ -116,6 +116,12 @@ var ai_enhanced_dialogue_enabled: bool = true
 # "full" response hydrates ai_enhanced_dialogue_enabled (server is authoritative for persisted state).
 var settings_response: Variant = null
 
+# v21 fields (#824, D-181): Economy snapshot from server.
+# Dictionary keyed by system_id → { price_current, price_trend, trade_flow_volume,
+# corporate_presence, stockpile_weeks, production_vs_baseline, official_coverage_ratio }
+# Null when no economy data in the current snapshot.
+var economy_snapshot: Variant = null
+
 # v7 fields (#431, D-059/D-060)
 var pending_recognitions: Array = []  # [{entity_id, x, y, z, remaining_ticks, total_delay_ticks}]
 

client/scripts/autoloads/hud_groups.gd

@@ -14,6 +14,7 @@ extends Node
 ##   "implant/map/starchart"   — star map navigator
 ##   "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")

client/scripts/main.gd

@@ -9,7 +9,6 @@ var _pending_record_inputs: Array = []  # #507: accumulates server-bound inputs
 var _router: SnapshotEventRouter  # #559: callable-based snapshot dispatch
 var _consumers: SnapshotConsumers  # #775: non-dialogue snapshot consumers
 var _dialogue: DialogueCoordinator  # #775: dialogue consumers + signal handlers
-
 @onready var world_renderer = $World
 @onready var fog_entities = $World/FogEntities  # D-059/D-060: cognitive delay fog visualization
 @onready var camera = $Camera2D
@@ -34,6 +33,7 @@ var _dialogue: DialogueCoordinator  # #775: dialogue consumers + signal handlers
 @onready var debug_console = $ModalLayer/DebugConsole  # #581: tilde debug console
 @onready var news_ticker = $UILayer/NewsTicker  # #592: scrolling headline bar (D-049 z-7)
 @onready var star_map = $InsertOverlay/HUD/StarMap  # #674: star map insert module (hop-ring view)
+@onready var economics_panel = $InsertOverlay/HUD/EconomicsPanel  # #824: economics monitor (D-170)
 
 
 func _ready() -> void:
@@ -92,6 +92,7 @@ func _ready() -> void:
 				"interaction_prompt": interaction_prompt,
 				"minimap": minimap,
 				"star_map": star_map,
+				"economics_panel": economics_panel,
 			},
 			_screen_flash
 		)
@@ -154,6 +155,7 @@ func _ready() -> void:
 	_router.register("dialogue_response", _dialogue.consume_dialogue_response)
 	_router.register("save_result", _consumers.consume_save_result)
 	_router.register("debug_response", _consumers.consume_debug_response)
+	_router.register("economy_snapshot", _consumers.consume_economy_snapshot)
 
 	# #581: Wire settings_dialog debug console toggle
 	if settings_dialog and debug_console:
@@ -170,6 +172,10 @@ func _unhandled_key_input(event: InputEvent) -> void:
 		if event is InputEventKey and event.keycode == KEY_M:
 			if star_map:
 				star_map.toggle_visible()
+		elif event is InputEventKey and event.keycode == KEY_E:
+			# #824: E — toggle Economics Monitor implant panel
+			if economics_panel:
+				economics_panel.toggle_visible()
 
 
 func _process(delta: float) -> void:

client/scripts/snapshot_consumers.gd

@@ -17,6 +17,7 @@ var interaction_list: Node = null
 var interaction_prompt: Node = null
 var minimap: Node = null
 var star_map: Node = null
+var economics_panel: Node = null  # #824: economics monitor (D-181)
 
 var _screen_flash_fn: Callable  # Callable(color: Color, duration: float)
 
@@ -37,6 +38,7 @@ func init(refs: Dictionary, screen_flash: Callable) -> SnapshotConsumers:
 	interaction_prompt = refs.get("interaction_prompt")
 	minimap = refs.get("minimap")
 	star_map = refs.get("star_map")
+	economics_panel = refs.get("economics_panel")
 	_screen_flash_fn = screen_flash
 	return self
 
@@ -54,6 +56,8 @@ func propagate_insert_state() -> void:
 		minimap.set_insert_active(insert_state)
 	if star_map:
 		star_map.set_insert_active(insert_state)
+	if economics_panel:
+		economics_panel.set_insert_active(insert_state)
 
 
 # D-057: Update interaction list from game state.
@@ -173,6 +177,14 @@ func consume_debug_response() -> void:
 	GameState.debug_response = null
 
 
+# #824: Forward economy_snapshot from server to the economics panel (D-181).
+func consume_economy_snapshot() -> void:
+	if GameState.economy_snapshot == null or not economics_panel:
+		return
+	if economics_panel.has_method("receive_economy_data"):
+		economics_panel.receive_economy_data(GameState.economy_snapshot)
+
+
 # #174: Consume examine result — show overlay when server sends character-filtered observation.
 func consume_examine_result() -> void:
 	if GameState.current_examine_result == null or not examine_display:

client/scripts/snapshot_handler.gd

@@ -213,6 +213,12 @@ static func apply(snapshot: Dictionary) -> void:
 	else:
 		GameState.settings_response = null
 
+	# v21: economy_snapshot (#824, D-181)
+	if snapshot.has("economy_snapshot") and snapshot.economy_snapshot is Dictionary:
+		GameState.economy_snapshot = snapshot.economy_snapshot
+	else:
+		GameState.economy_snapshot = null
+
 	# #718: character_visual_descriptor — restored from server snapshot on save/load.
 	if (
 		snapshot.has("character_visual_descriptor")