refactor(climate): ♻️ Improve anomaly handling with sorted keys and enforce proper typing for better performance and type safety

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

src/game/engine/src/modules/climate/atmosphere_anomalies.gd

@@ -164,7 +164,7 @@ func _drift_anomalies(game_map: RefCounted) -> void:
 
 	# Collect tiles with anomalies to drift
 	var drifters: Array = []
-	for pos: Variant in _anomaly_age.keys():
+	for pos: Vector2i in _sorted_anomaly_keys():
 		var tile: Variant = game_map.get_tile(pos)
 		if tile == null or tile.pressure_anomaly == 0.0:
 			_anomaly_age.erase(pos)
@@ -207,8 +207,8 @@ func _decay_and_reinforce_anomalies(game_map: RefCounted) -> void:
 	var reinforce: float = _p("anomaly_reinforce_rate")
 	var max_anomaly: float = _p("anomaly_max")
 
-	for pos: Variant in _anomaly_age.keys():
-		var tile: Variant = game_map.get_tile(pos)
+	for pos: Vector2i in _sorted_anomaly_keys():
+		var tile: Resource = game_map.get_tile(pos)
 		if tile == null:
 			continue
 
@@ -311,3 +311,18 @@ func _merge_anomalies(game_map: RefCounted) -> void:
 func _p(key: String) -> float:
 	## Read a param with fallback to defaults.
 	return float(_params.get(key, _DEFAULTS.get(key, 0.0)))
+
+
+func _sorted_anomaly_keys() -> Array[Vector2i]:
+	## Return `_anomaly_age` keys sorted by (x, y) so per-turn iteration
+	## is reproducible across processes — Dictionary insertion order drifts
+	## as keys are erased/re-added during drift, which silently desyncs
+	## pressure state between two otherwise-identical seed runs.
+	var keys: Array[Vector2i] = []
+	for k: Vector2i in _anomaly_age.keys():
+		keys.append(k)
+	keys.sort_custom(
+		func(a: Vector2i, b: Vector2i) -> bool:
+			return a.x < b.x if a.x != b.x else a.y < b.y
+	)
+	return keys