data_model: fix extract_doors — filter None values, fix structure

- Don't store attributes whose .value is None; avoids spurious "None"
  strings in the snapshot (lock_state, open_state were unset)
- Flatten the structure: overall lock_state/open_state now live directly
  under 'doors' instead of the double-nested 'doors.doors.overallState'
- Give vehicle.windows its own try/except, independent of vehicle.doors
- Capture doors.open_state (overall open state) which was missing before

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

server/data_model.py

@@ -180,23 +180,34 @@ def extract_doors(vehicle) -> dict | None:
 
     try:
         doors = vehicle.doors
-        result["doors"] = {
-            "overallState": _str(doors.lock_state),
-            "doors": {
-                name: {
-                    "lockState": _str(door.lock_state),
-                    "openState": _str(door.open_state),
-                }
-                for name, door in doors.doors.items()
-            },
-            "windows": {
-                name: {"openState": _str(win.open_state)}
-                for name, win in vehicle.windows.windows.items()
-            },
-        }
+        if doors.lock_state.value is not None:
+            result["lock_state"] = _str(doors.lock_state)
+        if doors.open_state.value is not None:
+            result["open_state"] = _str(doors.open_state)
+        door_entries = {}
+        for name, door in doors.doors.items():
+            entry = {}
+            if door.lock_state.value is not None:
+                entry["lock_state"] = _str(door.lock_state)
+            if door.open_state.value is not None:
+                entry["open_state"] = _str(door.open_state)
+            if entry:
+                door_entries[name] = entry
+        if door_entries:
+            result["doors"] = door_entries
     except Exception:
         log.debug("vehicle.doors unavailable", exc_info=True)
 
+    try:
+        window_entries = {}
+        for name, win in vehicle.windows.windows.items():
+            if win.open_state.value is not None:
+                window_entries[name] = {"open_state": _str(win.open_state)}
+        if window_entries:
+            result["windows"] = window_entries
+    except Exception:
+        log.debug("vehicle.windows unavailable", exc_info=True)
+
     return result or None