feat(client): initialize Godot 4 project boilerplate (epic #277)

Set up the complete Godot 4.6 client foundation as a pure renderer (D-020):
- project.godot with 2D rendering, autoloads, input actions
- Main scene: Game > World (TileMapLayer, Entities, FogOverlay) + Camera2D + UILayer
- Autoloads: SimBridge (connection state machine + test mode), GameState, InputMapper
- Rendering stubs: WorldRenderer, EntityRenderer, FogRenderer
- UI stubs: HUD (health/perception/time), Minimap, MonologueDisplay
- Input mapping: WASD/arrows, E (interact), Tab (perception), Esc (menu), Space (pause)
- gdUnit4 smoke tests: scene loads, autoloads registered (2/2 passing)

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

client/scripts/autoloads/game_state.gd

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+extends Node
+
+# Updated each frame from ObserverSnapshot data
+var current_snapshot: Dictionary = {}
+var player_position: Vector2 = Vector2.ZERO
+var visible_entities: Array = []
+var fog_state: Dictionary = {}
+var hud_data: Dictionary = {}
+
+func apply_snapshot(snapshot: Dictionary) -> void:
+	current_snapshot = snapshot
+
+	# Parse player data
+	if snapshot.has("player") and snapshot.player.has("position"):
+		var pos = snapshot.player.position
+		player_position = Vector2(pos[0], pos[1])
+
+	# Parse entities
+	if snapshot.has("entities"):
+		visible_entities = snapshot.entities
+
+	# Parse fog state
+	if snapshot.has("fog"):
+		fog_state = snapshot.fog
+
+	# Parse HUD data
+	if snapshot.has("hud"):
+		hud_data = snapshot.hud

client/scripts/autoloads/game_state.gd.uid

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+uid://dojylr6xlag0s

client/scripts/autoloads/input_mapper.gd

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+extends Node
+
+# Semantic actions — NO raw key codes cross the bridge
+enum Action {
+	MOVE_NORTH, MOVE_SOUTH, MOVE_EAST, MOVE_WEST,
+	INTERACT, USE_PERCEPTION_MODE, OPEN_MENU, PAUSE
+}
+
+var input_queue: Array[Dictionary] = []
+
+func _unhandled_input(event: InputEvent) -> void:
+	# Only process key press events (not releases or repeats)
+	if not event is InputEventKey:
+		return
+	if not event.pressed or event.echo:
+		return
+
+	var action: Action = -1
+	var action_name: String = ""
+
+	# Map input actions to semantic Action enum
+	if event.is_action_pressed("move_north"):
+		action = Action.MOVE_NORTH
+		action_name = "move_north"
+	elif event.is_action_pressed("move_south"):
+		action = Action.MOVE_SOUTH
+		action_name = "move_south"
+	elif event.is_action_pressed("move_east"):
+		action = Action.MOVE_EAST
+		action_name = "move_east"
+	elif event.is_action_pressed("move_west"):
+		action = Action.MOVE_WEST
+		action_name = "move_west"
+	elif event.is_action_pressed("interact"):
+		action = Action.INTERACT
+		action_name = "interact"
+	elif event.is_action_pressed("perception_mode"):
+		action = Action.USE_PERCEPTION_MODE
+		action_name = "perception_mode"
+	elif event.is_action_pressed("open_menu"):
+		action = Action.OPEN_MENU
+		action_name = "open_menu"
+	elif event.is_action_pressed("pause"):
+		action = Action.PAUSE
+		action_name = "pause"
+
+	# Queue the action if valid
+	if action != -1:
+		input_queue.append({
+			"action": action,
+			"timestamp_msec": Time.get_ticks_msec()
+		})
+		get_viewport().set_input_as_handled()
+
+func flush_queue() -> Array[Dictionary]:
+	var queue = input_queue.duplicate()
+	input_queue.clear()
+	return queue

client/scripts/autoloads/input_mapper.gd.uid

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+uid://censpds5c1g8r

client/scripts/autoloads/sim_bridge.gd

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+extends Node
+
+# Connection states
+enum ConnectionState { DISCONNECTED, CONNECTING, CONNECTED, ERROR }
+
+var state: ConnectionState = ConnectionState.DISCONNECTED
+var test_mode: bool = true  # Enable test mode for development without Rust server
+
+# Signals
+signal connection_state_changed(old_state: ConnectionState, new_state: ConnectionState)
+signal snapshot_received(snapshot: Dictionary)
+
+func _ready() -> void:
+	if test_mode:
+		print("SimBridge: Running in test mode (hardcoded snapshot)")
+
+# Change connection state and emit signal
+func _set_state(new_state: ConnectionState) -> void:
+	if state != new_state:
+		var old_state = state
+		state = new_state
+		connection_state_changed.emit(old_state, new_state)
+
+# Connect to simulation server (real implementation comes later)
+func connect_to_sim() -> void:
+	_set_state(ConnectionState.CONNECTING)
+	# TODO: Actual connection logic when IPC/MessagePack is implemented
+	if test_mode:
+		_set_state(ConnectionState.CONNECTED)
+	else:
+		_set_state(ConnectionState.ERROR)
+
+# Disconnect from simulation server
+func disconnect_from_sim() -> void:
+	_set_state(ConnectionState.DISCONNECTED)
+
+# Send input to simulation (real implementation comes later)
+func send_input(player_input: Dictionary) -> void:
+	if state != ConnectionState.CONNECTED:
+		return
+	# TODO: Serialize and send via MessagePack when IPC is implemented
+	pass
+
+# Poll for snapshot from simulation
+func poll_snapshot() -> Variant:
+	if state != ConnectionState.CONNECTED:
+		return null
+
+	if test_mode:
+		var snapshot = _test_snapshot()
+		snapshot_received.emit(snapshot)
+		return snapshot
+
+	# TODO: Actual polling logic when IPC/MessagePack is implemented
+	return null
+
+# Hardcoded test snapshot for development
+func _test_snapshot() -> Dictionary:
+	return {
+		"tick": Time.get_ticks_msec() / 100,  # Increment over time for testing
+		"player": {
+			"position": [10, 10],
+			"health": 100
+		},
+		"entities": [
+			{
+				"id": 1,
+				"type": "npc",
+				"position": [12, 8],
+				"name": "Test NPC"
+			},
+		],
+		"fog": {
+			"radius": 8
+		},
+		"hud": {
+			"perception_mode": "baseline",
+			"time": "08:00"
+		}
+	}

client/scripts/autoloads/sim_bridge.gd.uid

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+uid://cmjlrxs0vkvbb