feat(inventory)!: lock warehouses permanently to their parent project

Warehouses now belong strictly and exclusively to the project they were created under; cross-project reassignment is removed end-to-end.

Backend: PATCH /inventory/warehouses/{id} no longer applies project_id — any attempt to move a warehouse to a different project returns 400 with «پروژه‌ی انبار قابل تغییر نیست — انبار برای همیشه به پروژه‌ی والدش تعلق دارد» (sending the current project stays a harmless no-op). The WarehouseUpdate schema documents project_id as accept-only-to-reject; creation still requires project_id and delete is unchanged.

Frontend: the Organization page's per-warehouse project dropdown («انتقال به پروژه دیگر») and its moveWarehouse handler are removed — warehouses render statically inside their project card with only the dashboard link and delete; the warehouses.update API type no longer accepts project_id. WarehousesPage already had no move UI (rename/describe only).

Verified end-to-end against the running stack: rename 200; same-project project_id no-op 200; cross-project reassignment 400 with the guard message; warehouse remains in its original project; test data cleaned up. python compile + api/frontend builds clean.

backend/app/schemas/inventory.py

@@ -30,6 +30,13 @@ class WarehouseCreate(APIModel):
 
 
 class WarehouseUpdate(APIModel):
+    """Rename/re-describe a warehouse.
+
+    `project_id` is accepted only to be rejected: a warehouse belongs
+    permanently to its parent project and cannot be reassigned (the router
+    answers 400 unless the value equals the current project).
+    """
+
     name: str | None = Field(default=None, min_length=1, max_length=255)
     description: str | None = None
     project_id: UUID | None = None