Move doors to door manager

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/features/map/door.dart

@@ -0,0 +1,56 @@
+enum DoorState { closed, opening, open, closing }
+
+class Door {
+  final int x;
+  final int y;
+  final int mapId; // To differentiate between regular doors and elevator doors
+
+  DoorState state = DoorState.closed;
+  double offset = 0.0;
+  int openTime = 0; // When did the door fully open?
+
+  // How long a door stays open before auto-closing
+  static const int openDurationMs = 3000;
+
+  Door({
+    required this.x,
+    required this.y,
+    required this.mapId,
+  });
+
+  // Returns true if the door state changed this frame (useful for playing sounds later)
+  bool update(int currentTimeMs) {
+    bool stateChanged = false;
+
+    if (state == DoorState.opening) {
+      offset += 0.02; // Slide speed
+      if (offset >= 1.0) {
+        offset = 1.0;
+        state = DoorState.open;
+        openTime = currentTimeMs;
+        stateChanged = true;
+      }
+    } else if (state == DoorState.open) {
+      if (currentTimeMs - openTime > openDurationMs) {
+        state = DoorState.closing;
+        stateChanged = true;
+      }
+    } else if (state == DoorState.closing) {
+      // Note: We don't check for entities blocking the door yet!
+      offset -= 0.02;
+      if (offset <= 0.0) {
+        offset = 0.0;
+        state = DoorState.closed;
+        stateChanged = true;
+      }
+    }
+
+    return stateChanged;
+  }
+
+  void interact() {
+    if (state == DoorState.closed || state == DoorState.closing) {
+      state = DoorState.opening;
+    }
+  }
+}