feat: add Chinese UI, Responses models, and mirrored Windows setup

Localize the web console and persist custom model and capability settings.
Use OpenAI Responses exclusively and move runtime limits into environment configuration.
Bootstrap uv and the virtual environment on Windows, support optional China mirrors,
and package source distributions without environments, build output, or credentials.

Update regression tests and repository quality checks for the new behavior.

playground/backend_manager/app/auth/jwt_handler.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timedelta, timezone, UTC
 from fastapi import Depends, HTTPException, Security, status
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from jose import JWTError, jwt
@@ -23,13 +23,11 @@ security = HTTPBearer(auto_error=False)
 
 def create_access_token(user_id: str, extra_claims: dict | None = None) -> str:
     """Generate a signed JWT access token."""
-    expire = datetime.now(timezone.utc) + timedelta(
-        minutes=settings.JWT_ACCESS_TOKEN_EXPIRE_MINUTES
-    )
+    expire = datetime.now(UTC) + timedelta(minutes=settings.JWT_ACCESS_TOKEN_EXPIRE_MINUTES)
     to_encode = {
         "sub": user_id,
         "exp": expire,
-        "iat": datetime.now(timezone.utc),
+        "iat": datetime.now(UTC),
         "iss": "artemis-backend-manager",
     }
     if extra_claims:

playground/backend_manager/app/auth/otp_service.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timedelta, timezone, UTC
 import logging
 import secrets
 from app.config import settings
@@ -38,7 +38,7 @@ class OTPService:
         else:
             code = f"{secrets.randbelow(900000) + 100000}"
 
-        expires_at = datetime.now(timezone.utc) + timedelta(seconds=settings.OTP_EXPIRE_SECONDS)
+        expires_at = datetime.now(UTC) + timedelta(seconds=settings.OTP_EXPIRE_SECONDS)
         self._store[ident] = {
             "code": code,
             "expires_at": expires_at,
@@ -65,7 +65,7 @@ class OTPService:
             logger.warning(f"[OTP Service] No active OTP found for {ident}")
             return False
 
-        if datetime.now(timezone.utc) > record["expires_at"]:
+        if datetime.now(UTC) > record["expires_at"]:
             logger.warning(f"[OTP Service] OTP for {ident} has expired")
             self._store.pop(ident, None)
             return False

playground/backend_manager/app/services/bigquery_service.py

@@ -34,7 +34,7 @@ class BigQueryMappingService:
 
     def __init__(self):
         self._local_cache: dict[str, SessionRecord] = {}
-        self._client: Optional["bigquery.Client"] = None
+        self._client: bigquery.Client | None = None
         self._table_ref: str = (
             f"{settings.GCP_PROJECT_ID}.{settings.BQ_DATASET}.{settings.BQ_TABLE}"
         )

playground/backend_manager/app/services/docker_service.py

@@ -33,7 +33,7 @@ class DockerManagerService:
     """Manages creation, monitoring, and deletion of ephemeral Artemis session containers via Docker Socket."""
 
     def __init__(self):
-        self._client: Optional["docker.DockerClient"] = None
+        self._client: docker.DockerClient | None = None
         if DOCKER_AVAILABLE:
             try:
                 self._client = docker.DockerClient(base_url=settings.DOCKER_SOCKET_PATH)

playground/backend_manager/app/services/session_manager.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import asyncio
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timedelta, timezone, UTC
 import logging
 import uuid
 from app.config import settings
@@ -49,7 +49,7 @@ class SessionManagerService:
         while True:
             try:
                 await asyncio.sleep(settings.REAPER_CHECK_INTERVAL_SECONDS)
-                now = datetime.now(timezone.utc)
+                now = datetime.now(UTC)
                 active_sessions = await bigquery_service.list_all_active_sessions()
 
                 for s in active_sessions:
@@ -78,7 +78,7 @@ class SessionManagerService:
     async def create_session(self, user_id: str, request: CreateSessionRequest) -> SessionResponse:
         """Provision a new Cuttlefish emulator + Artemis container and link them via ADB."""
         session_id = str(uuid.uuid4())
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         expires_at = now + timedelta(minutes=request.ttl_minutes)
 
         logger.info(
@@ -164,7 +164,7 @@ class SessionManagerService:
         if not record or record.user_id != user_id or record.status == SessionStatus.TERMINATED:
             return None
 
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         record.last_heartbeat_at = now
         record.expires_at = now + timedelta(minutes=settings.SESSION_TTL_MINUTES)
         await bigquery_service.save_session(record)