fix(client): anchor camera to player before first frame renders

Camera2D's internal smoothed_camera_pos starts at (0,0) and lerps
toward global_position, causing a visible white-screen drift on startup.
Disable position_smoothing in _ready(), snap camera to player position
from the first snapshot, then re-enable smoothing with reset_smoothing()
after the first anchored frame. Add tick guards to monologue/dialogue
consumption to prevent re-triggering when client FPS > sim tick rate.

Fixes bug #2 (camera doesn't center on player at startup).

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

client/scripts/main.gd

@@ -17,24 +17,54 @@ extends Node2D
 # If a new snapshot arrives with null dialogue while fade-in is still running,
 # we don't re-trigger show_dialogue because _last_dialogue_id still matches.
 var _last_dialogue_id: int = 0
+var _camera_anchored: bool = false
+var _last_monologue_tick: int = -1  # Prevent re-consuming monologue when same tick polled twice
+var _last_dialogue_tick: int = -1
 
 func _ready() -> void:
 	print("The Settled Reach — client initialized")
 
-	# Connect to simulation (will use test mode initially)
+	# Disable camera smoothing during init. Camera2D's position_smoothing
+	# lerps an internal smoothed_camera_pos toward global_position each frame.
+	# That smoothed position initializes at (0,0) — the Camera2D's default in
+	# the .tscn. Even after we set global_position to the player coords,
+	# smoothing causes the viewport to still show (0,0) on the first rendered
+	# frame because the lerp hasn't converged. With smoothing OFF, the viewport
+	# uses global_position directly. Re-enabled in _process() after anchor.
+	camera.position_smoothing_enabled = false
+
+	# Connect to simulation (test mode sets CONNECTED immediately)
 	SimBridge.connect_to_sim()
 
+	# Camera anchor: snap to player position before the first frame renders.
+	# In test mode poll_snapshot() returns synchronously — position is set
+	# immediately. In live mode the snapshot isn't available yet — _process
+	# handles it. No reset_smoothing() needed: smoothing is OFF.
+	var first_snapshot: Variant = SimBridge.poll_snapshot()
+	if first_snapshot != null:
+		GameState.apply_snapshot(first_snapshot)
+		camera.global_position = GameState.player_position * Constants.TILE_SIZE
+		_camera_anchored = true
+
 	# D-061: Connect dialogue box signals
 	if dialogue_box:
 		dialogue_box.option_selected.connect(_on_dialogue_option_selected)
 		dialogue_box.dialogue_dismissed.connect(_on_dialogue_dismissed)
 
+
 func _process(_delta: float) -> void:
 	# Main game loop: poll snapshot, apply state, flush input
-	var snapshot = SimBridge.poll_snapshot()
+	var snapshot: Variant = SimBridge.poll_snapshot()
 	if snapshot != null:
 		GameState.apply_snapshot(snapshot)
 
+		# Late anchor: live mode — first snapshot arrives during _process.
+		# Smoothing is already OFF (disabled in _ready), so setting
+		# global_position takes effect immediately with no lerp.
+		if not _camera_anchored:
+			camera.global_position = GameState.player_position * Constants.TILE_SIZE
+			_camera_anchored = true
+
 		# Update renderers with new state
 		if world_renderer and world_renderer.has_method("update_from_state"):
 			world_renderer.update_from_state()
@@ -62,8 +92,16 @@ func _process(_delta: float) -> void:
 		_consume_dialogue()
 
 	# Track camera to player position every frame (D-015: locked, no panning)
-	# Camera2D smoothing handles interpolation — we just set the target
-	camera.global_position = GameState.player_position * Constants.TILE_SIZE
+	if _camera_anchored:
+		camera.global_position = GameState.player_position * Constants.TILE_SIZE
+
+	# Re-enable smoothing after the first anchored frame. The frame that just
+	# rendered used smoothing=OFF (correct viewport from frame one). Now we
+	# turn smoothing back on and sync its internal state so subsequent frames
+	# get smooth camera tracking during gameplay.
+	if _camera_anchored and not camera.position_smoothing_enabled:
+		camera.position_smoothing_enabled = true
+		camera.reset_smoothing()
 
 	# Send queued input to simulation
 	var inputs = InputMapper.flush_queue()
@@ -92,24 +130,31 @@ func _process(_delta: float) -> void:
 		SimBridge.send_input(input)
 
 
-# Consume-once: show monologue text, then clear to prevent re-display.
-# Single monologue per snapshot is guaranteed by server.
+# Consume-once per tick: show monologue text, then clear.
+# Tick guard prevents re-triggering when the same tick is polled multiple
+# times (client FPS > sim tick rate).
 func _consume_monologue() -> void:
-	if GameState.current_monologue != null and monologue_display:
-		var mono: Dictionary = GameState.current_monologue
-		monologue_display.show_monologue(mono.get("text", ""), mono.get("duration_seconds", 5.0))
-		GameState.current_monologue = null
+	if GameState.current_monologue == null or not monologue_display:
+		return
+	if GameState.current_tick == _last_monologue_tick:
+		return
+	_last_monologue_tick = GameState.current_tick
+	var mono: Dictionary = GameState.current_monologue
+	monologue_display.show_monologue(mono.get("text", ""), mono.get("duration_seconds", 5.0))
+	GameState.current_monologue = null
 
 
-# Consume-once with ID tracking: show dialogue, then clear.
-# Uses dialogue_id to avoid re-triggering during fade-in if a null snapshot arrives.
+# Consume-once per tick with ID tracking: show dialogue, then clear.
+# Tick guard + is_dialogue_active check prevent re-triggering.
 func _consume_dialogue() -> void:
 	if GameState.current_dialogue == null or not dialogue_box:
 		return
-	# Don't re-show the same dialogue if it's already active with the same content
+	if GameState.current_tick == _last_dialogue_tick:
+		return
 	if dialogue_box.is_dialogue_active():
 		GameState.current_dialogue = null
 		return
+	_last_dialogue_tick = GameState.current_tick
 	var dlg: Dictionary = GameState.current_dialogue
 	dialogue_box.show_dialogue(
 		dlg.get("npc_name", ""),