fix(client): address PR review — invalidation, constants, tests

Review feedback from Hoshe + Tyre on PR #8:

- Extract shared TILE_SIZE to Constants class_name (Tyre #5, Hoshe #7)
- Fix tile invalidation: detect tile/visibility count changes instead
  of one-shot dirty flag, supports chunk loading (Tyre #3, #4)
- Fog dirty tracking: only re-render when visible_positions changes
- Add bounds warning for unknown tile types (Hoshe #1)
- Add player-not-found warning in GameState (Hoshe #5)
- Use Image.fill_rect() instead of pixel loops (Tyre #10)
- Document _player_pos as reserved for fog decay #113 (Tyre #6)
- Add TODO(#130) for D-033 relationship colors (Hoshe #3, Tyre #8)
- Add class_name to EntityRenderer, FogRenderer, TileRenderer
- 20 new rendering tests (D-030 Layer 1): entity lifecycle, fog
  registration, tile type mapping, snapshot completeness, constants
- 65 total tests passing, 0 failures

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

client/scripts/rendering/fog_renderer.gd

@@ -1,3 +1,4 @@
+class_name FogRenderer
 extends TileMapLayer
 
 # Fog renderer — draws fog overlay on non-visible tiles (D-011)
@@ -9,8 +10,12 @@ extends TileMapLayer
 # Atlas layout:
 #   (0,0) = full fog (opaque black)
 #   (1,0) = fog edge (semi-transparent)
+#
+# Note: fog-edge uses 8-directional neighbors for visual smoothness.
+# Actual visibility boundaries come from the server's shadowcasting (D-011).
+# Fog-returns-over-time (D-011 decay) is tracked in #113, not here.
 
-const TILE_SIZE: int = 32
+const TILE_SIZE: int = Constants.TILE_SIZE
 
 var _initialized: bool = false
 var _all_tile_positions: Dictionary = {}  # Vector2i -> true, all known map tiles
@@ -28,9 +33,9 @@ func _setup_tileset() -> void:
 	var img := Image.create(TILE_SIZE * 2, TILE_SIZE, false, Image.FORMAT_RGBA8)
 
 	# Full fog (0,0) — opaque black
-	_fill_tile(img, 0, Color(0.02, 0.02, 0.05, 1.0))
+	img.fill_rect(Rect2i(0, 0, TILE_SIZE, TILE_SIZE), Color(0.02, 0.02, 0.05, 1.0))
 	# Fog edge (1,0) — semi-transparent dark
-	_fill_tile(img, 1, Color(0.02, 0.02, 0.05, 0.6))
+	img.fill_rect(Rect2i(TILE_SIZE, 0, TILE_SIZE, TILE_SIZE), Color(0.02, 0.02, 0.05, 0.6))
 
 	var tex := ImageTexture.create_from_image(img)
 	source.texture = tex
@@ -49,8 +54,8 @@ func register_tile_positions(tiles: Array) -> void:
 		if tile_data.has("x") and tile_data.has("y"):
 			_all_tile_positions[Vector2i(tile_data.x, tile_data.y)] = true
 
-# Update fog based on visible positions
-# visible_positions: Dictionary of Vector2i -> true
+# Update fog based on visible positions.
+# player_pos reserved for future fog-decay tracking (#113).
 func update_fog(visible_positions: Dictionary, _player_pos: Vector2) -> void:
 	if not _initialized:
 		return
@@ -60,7 +65,7 @@ func update_fog(visible_positions: Dictionary, _player_pos: Vector2) -> void:
 	if _all_tile_positions.is_empty() or visible_positions.is_empty():
 		return
 
-	# Build set of fog-edge positions (adjacent to visible but not visible themselves)
+	# Build set of fog-edge positions (8-directional neighbors of visible tiles)
 	var fog_edge: Dictionary = {}
 	var neighbors := [
 		Vector2i(-1, 0), Vector2i(1, 0), Vector2i(0, -1), Vector2i(0, 1),
@@ -81,9 +86,3 @@ func update_fog(visible_positions: Dictionary, _player_pos: Vector2) -> void:
 			set_cell(pos, 0, Vector2i(1, 0))  # Fog edge — semi-transparent
 		else:
 			set_cell(pos, 0, Vector2i(0, 0))  # Full fog — opaque
-
-func _fill_tile(img: Image, tile_index: int, color: Color) -> void:
-	var x_offset := tile_index * TILE_SIZE
-	for x in range(TILE_SIZE):
-		for y in range(TILE_SIZE):
-			img.set_pixel(x_offset + x, y, color)