feat(admin/models): delete an added model with inline confirm

Backend: AiModelRepository.delete() + DELETE /api/admin/models/{id} (owner-only,
audited) in the RPC-served admin router; session commits per request.
Frontend: api.adminDeleteModel() (WebSocket RPC DELETE) and a per-row حذف
action with a two-step inline confirm (تأیید حذف / انصراف) that removes the
row from state on success. tsc clean, py_compile clean.

apps/api/app/infrastructure/repositories/ai_control.py

@@ -281,6 +281,14 @@ class AiModelRepository:
         await self.session.flush()
         return _model_to_domain(row)
 
+    async def delete(self, model_id: str) -> bool:
+        row = await self.session.get(AiModelRow, model_id)
+        if row is None:
+            return False
+        await self.session.delete(row)
+        await self.session.flush()
+        return True
+
     async def pick_for_mode(self, mode: RoutingMode) -> AiModel | None:
         """Choose a model for a routing mode.