feat: 扩展 Rust gateway 全功能模块，新增 billing/crypto/wallet crate 及完整数据层

- 新增 aether-billing、aether-crypto、aether-wallet 独立 crate
- aether-data 扩展 repository 层：announcements、auth_modules、billing、
  candidate_selection、gemini_file_mappings、global_models、management_tokens、
  oauth_providers、proxy_nodes、quota、users、wallet 等模块
- aether-gateway 新增 api/auth/billing/control/middleware/scheduler/usage/
  video_tasks/hooks/maintenance/model_fetch/provider_transport 等功能模块
- 重构 executor decision 和 gateway state 为模块目录结构
- 新增 gateway router、frontdoor 路由层及对应测试
- Python 侧 API 路由重构，新增 compat/support 模块
- 前端 Logo 组件更新及 Provider 管理页面调整

tests/services/test_upstream_fetcher_rust.py

@@ -191,7 +191,7 @@ async def test_fetch_models_from_endpoints_uses_rust_for_gemini(
 
 
 @pytest.mark.asyncio
-async def test_fetch_models_from_endpoints_falls_back_to_python_when_rust_unavailable(
+async def test_fetch_models_from_endpoints_returns_rust_only_error_when_rust_unavailable(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     monkeypatch.setattr(fetcher_mod.config, "executor_backend", "rust")
@@ -224,7 +224,7 @@ async def test_fetch_models_from_endpoints_falls_back_to_python_when_rust_unavai
         timeout=1.0,
     )
 
-    assert ok is True
-    assert errors == []
-    assert models == [{"id": "fallback-model", "api_format": "openai:chat"}]
-    python_fetch.assert_awaited_once()
+    assert ok is False
+    assert models == []
+    assert errors == ["openai:chat: rust executor unavailable"]
+    python_fetch.assert_not_awaited()