fix(assets): tune fog shader alpha and add zone temperature tint per D-059

Ticket #563. Light fog alpha tuned to 0.25-0.35 range (was 0.25-0.55),
deep fog alpha set to 0.55-0.70 with zone temperature tint from
zone_tint_tex (bar=warm #2a1f15, hub=cool #1a1f2e, corridor=neutral
#1a1a1a). Two Perlin noise cycles: 8-10s light, 15-20s deep.
Zone tint texture now populated per-tile from server zone_id in
fog_state.gd with preservation across texture resizes.

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

client/scripts/autoloads/fog_state.gd

@@ -15,6 +15,20 @@ const EXP_UNEXPLORED: int = 0   # Never seen — total darkness
 const EXP_EXPLORED: int = 128   # Previously seen, now out of LOS — deep fog
 const EXP_VISIBLE: int = 255    # Currently in LOS — clear (written each frame)
 
+# Zone temperature tints (D-059 + D-046, Sprint 22) — keyed by zone_id string from server.
+# Matches audio_manager.gd ZONE_ASSETS zone_id strings for consistent zone semantics.
+# Colors are dark tints used as the fog overlay in the deep fog zone:
+#   hub/workplace: #1a1f2e (cool blue-dark — terminal, institutional)
+#   bar:           #2a1f15 (warm amber-dark — social, inhabited)
+#   corridor:      #1a1a1a (neutral dark — transitional, maintenance)
+const ZONE_TINTS: Dictionary = {
+	"hub":       Color(0.102, 0.122, 0.180),  # #1a1f2e — cool blue-dark
+	"workplace": Color(0.102, 0.122, 0.180),  # same as hub
+	"bar":       Color(0.165, 0.122, 0.082),  # #2a1f15 — warm amber-dark
+	"corridor":  Color(0.102, 0.102, 0.102),  # #1a1a1a — neutral dark
+}
+const ZONE_TINT_DEFAULT: Color = Color(0.102, 0.102, 0.102)  # #1a1a1a neutral
+
 var map_bounds: Rect2i = Rect2i(0, 0, 1, 1)
 var visibility_texture: ImageTexture
 var exploration_texture: ImageTexture
@@ -25,6 +39,8 @@ var _exp_bytes: PackedByteArray
 var _vis_image: Image
 var _exp_image: Image
 var _tint_image: Image
+# Zone tint stored as 3-channel RGB bytes (R, G, B per pixel) for preservation across resizes
+var _tint_bytes: PackedByteArray
 var _width: int = 1
 var _height: int = 1
 var _prev_visible: Dictionary = {}  # Tiles visible last frame (for incremental decay)
@@ -37,6 +53,7 @@ func _ready() -> void:
 func _resize(bounds: Rect2i) -> void:
 	var old_bounds := map_bounds
 	var old_exp := _exp_bytes
+	var old_tint := _tint_bytes
 	var old_w := _width
 	var old_h := _height
 
@@ -72,9 +89,35 @@ func _resize(bounds: Rect2i) -> void:
 	_exp_image = Image.create_from_data(_width, _height, false, Image.FORMAT_R8, _exp_bytes)
 	exploration_texture = ImageTexture.create_from_image(_exp_image)
 
-	# Zone tint — neutral dark for Sprint 6 (zone metadata deferred)
-	_tint_image = Image.create(_width, _height, false, Image.FORMAT_RGB8)
-	_tint_image.fill(Color(0.05, 0.05, 0.08))
+	# Zone tint — 3 bytes per pixel (RGB), default neutral dark
+	var tint_sz := sz * 3
+	_tint_bytes = PackedByteArray()
+	_tint_bytes.resize(tint_sz)
+	var default_r := int(ZONE_TINT_DEFAULT.r * 255.0)
+	var default_g := int(ZONE_TINT_DEFAULT.g * 255.0)
+	var default_b := int(ZONE_TINT_DEFAULT.b * 255.0)
+	for i in range(sz):
+		_tint_bytes[i * 3 + 0] = default_r
+		_tint_bytes[i * 3 + 1] = default_g
+		_tint_bytes[i * 3 + 2] = default_b
+	# Preserve zone tint data from old bounds (zone tints are stable — tile zone never changes)
+	if old_tint.size() > 0 and old_w > 0 and old_h > 0:
+		var dx: int = old_bounds.position.x - bounds.position.x
+		var dy: int = old_bounds.position.y - bounds.position.y
+		for oy in range(old_h):
+			var ny: int = oy + dy
+			if ny < 0 or ny >= _height:
+				continue
+			for ox in range(old_w):
+				var nx: int = ox + dx
+				if nx < 0 or nx >= _width:
+					continue
+				var old_idx := (oy * old_w + ox) * 3
+				var new_idx := (ny * _width + nx) * 3
+				_tint_bytes[new_idx + 0] = old_tint[old_idx + 0]
+				_tint_bytes[new_idx + 1] = old_tint[old_idx + 1]
+				_tint_bytes[new_idx + 2] = old_tint[old_idx + 2]
+	_tint_image = Image.create_from_data(_width, _height, false, Image.FORMAT_RGB8, _tint_bytes)
 	zone_tint_texture = ImageTexture.create_from_image(_tint_image)
 
 	_prev_visible.clear()
@@ -126,6 +169,35 @@ func update_from_state() -> void:
 	_exp_image.set_data(_width, _height, false, Image.FORMAT_R8, _exp_bytes)
 	exploration_texture.update(_exp_image)
 
+	# 3. Zone tint: write zone temperature color for currently visible tiles.
+	#    Zone data is stable (tile zone never changes) so we only write on first sight.
+	#    Data persists in _tint_bytes across frames and across resizes.
+	var tint_dirty := false
+	for tile in tiles:
+		if not tile is Dictionary or not tile.has("x") or not tile.has("y"):
+			continue
+		var zone_id: String = str(tile.get("zone_id", ""))
+		if zone_id.is_empty():
+			continue
+		var tint_color: Color = ZONE_TINTS.get(zone_id, ZONE_TINT_DEFAULT)
+		var px: int = int(tile.x) - ox
+		var py: int = int(tile.y) - oy
+		if px < 0 or py < 0 or px >= _width or py >= _height:
+			continue
+		var tint_idx := (py * _width + px) * 3
+		var new_r := int(tint_color.r * 255.0)
+		var new_g := int(tint_color.g * 255.0)
+		var new_b := int(tint_color.b * 255.0)
+		# Only update if different from current (avoid spurious texture uploads)
+		if _tint_bytes[tint_idx] != new_r or _tint_bytes[tint_idx + 1] != new_g or _tint_bytes[tint_idx + 2] != new_b:
+			_tint_bytes[tint_idx + 0] = new_r
+			_tint_bytes[tint_idx + 1] = new_g
+			_tint_bytes[tint_idx + 2] = new_b
+			tint_dirty = true
+	if tint_dirty:
+		_tint_image.set_data(_width, _height, false, Image.FORMAT_RGB8, _tint_bytes)
+		zone_tint_texture.update(_tint_image)
+
 	# Shallow copy — correct for Dictionary<Vector2i, bool/String> values
 	_prev_visible = positions.duplicate()