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.

tests/unit/admin_console/test_step_repository.py

@@ -56,7 +56,7 @@ def test_retrying_llm_payload_keeps_user_visible_retry_details():
             {
                 "error": "503 UNAVAILABLE: high demand",
                 "delay": 1.18,
-                "provider": "google",
+                "provider": "openai",
                 "source": "provider_sdk",
                 "recoverable": True,
                 "internal_noise": "do not expose",
@@ -69,7 +69,7 @@ def test_retrying_llm_payload_keeps_user_visible_retry_details():
     assert normalized["payload"] == {
         "error": "503 UNAVAILABLE: high demand",
         "delay": 1.18,
-        "provider": "google",
+        "provider": "openai",
         "source": "provider_sdk",
         "recoverable": True,
     }
@@ -81,7 +81,7 @@ def test_terminal_llm_payload_keeps_wait_and_retry_aggregation():
         {
             "delay": 5.0,
             "scheduled_at": 100.0,
-            "provider": "google",
+            "provider": "openai",
             "source": "provider_sdk",
         }
     ]
@@ -94,7 +94,7 @@ def test_terminal_llm_payload_keeps_wait_and_retry_aggregation():
                 "error": "503 UNAVAILABLE",
                 "pause": True,
                 "request_id": "request-1",
-                "provider": "google",
+                "provider": "openai",
                 "waited_seconds": 18.5,
                 "retries": retries,
                 "messages": ["private prompt"],
@@ -106,7 +106,7 @@ def test_terminal_llm_payload_keeps_wait_and_retry_aggregation():
 
     assert normalized["payload"] == {
         "error": "503 UNAVAILABLE",
-        "provider": "google",
+        "provider": "openai",
         "pause": True,
         "request_id": "request-1",
         "waited_seconds": 18.5,