refactor: Antigravity/Codex 服务重构为插件化适配器架构

- 将 Antigravity 和 Codex 从独立模块迁移至 src/services/provider/adapters/ 插件体系
- 新增 provider_types 和 oauth_token 模块，移除 maintenance_scheduler 中的 OAuth 定时刷新
- 增强 admin API：扩展 keys 和 provider_query 端点，新增 dashboard 路由
- 大幅增强 ProviderDetailDrawer 组件，新增 AntigravityQuotaDialog
- 改进 handler 基类（chat/cli）和错误分类器
- 优化 fetch_scheduler 和 upstream_fetcher
- 前端 UI 组件清理和优化
- 更新测试以匹配新模块结构

tests/services/test_codex_request.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from src.services.provider.codex import (
+from src.services.provider.adapters.codex.request_patching import (
     maybe_patch_request_for_codex,
     patch_openai_cli_request_for_codex,
 )
@@ -106,7 +106,7 @@ def test_maybe_patch_request_for_codex_patches_for_codex_openai_cli() -> None:
 
 
 def test_codex_envelope_extra_headers_includes_sse_accept_and_session() -> None:
-    from src.services.codex.envelope import codex_oauth_envelope
+    from src.services.provider.adapters.codex.envelope import codex_oauth_envelope
 
     headers = codex_oauth_envelope.extra_headers() or {}
     assert headers.get("Accept") == "text/event-stream"