refactor: 共享请求管道、按需懒加载、流式内存护栏与连接池治理

- 抽取 ApiRequestPipeline 单例，44 个路由文件共享同一实例
- Handler/Adapter 模块级 __getattr__ 延迟导入，减少启动时间
- 新增 ensure_stream_buffer_limit() 流式内存护栏（16MB 单行 / 32MB 总量）
- HTTP 空闲连接清理与 curl_cffi LRU 会话池
- ensure_providers_bootstrapped 按需引导指定 provider_types
- Usage 事件序列化迁移至 msgpack，Redis codec 隔离
- 启动预热任务（/readyz 就绪门控）与优雅关闭
- 通知邮件模块独立开关与 SMTP 配置校验
- CryptoService DCL 线程安全修复
- 通知模块开关 DB 查询 30s 内存缓存
- /readyz 对 unknown 状态返回 503
- 预热关闭 5s 超时保护
- 预热适配器逐个 try-except 容错
- FormatConversionRegistry 哨兵模式防并发重复物化
- 流式缓冲检查无条件执行

Closes #230

Co-authored-by: AAEE86 <ppk0227@hotmail.com>

tests/services/test_quota_reader.py

@@ -88,6 +88,72 @@ def test_extract_reset_seconds_uses_codex_weekly_reset_for_codex_provider() -> N
     assert extract_reset_seconds(key_obj) == pytest.approx(1800.0)
 
 
+def test_extract_reset_seconds_prefers_codex_reset_at(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("src.services.provider.pool.dimensions._helpers.time.time", lambda: 1000.0)
+    key_obj = SimpleNamespace(
+        provider_type="codex",
+        upstream_metadata={
+            "codex": {
+                "primary_reset_at": 1200.0,
+                "primary_reset_seconds": 9999.0,
+            }
+        },
+    )
+
+    assert extract_reset_seconds(key_obj) == pytest.approx(200.0)
+
+
+def test_extract_reset_seconds_codex_fallback_corrects_elapsed(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr("src.services.provider.pool.dimensions._helpers.time.time", lambda: 2000.0)
+    key_obj = SimpleNamespace(
+        provider_type="codex",
+        upstream_metadata={
+            "codex": {
+                "primary_reset_seconds": 180.0,
+                "updated_at": 1900.0,
+            }
+        },
+    )
+
+    assert extract_reset_seconds(key_obj) == pytest.approx(80.0)
+
+
+def test_extract_reset_seconds_codex_fallback_clamps_to_zero(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr("src.services.provider.pool.dimensions._helpers.time.time", lambda: 2000.0)
+    key_obj = SimpleNamespace(
+        provider_type="codex",
+        upstream_metadata={
+            "codex": {
+                "primary_reset_seconds": 120.0,
+                "updated_at": 1500.0,
+            }
+        },
+    )
+
+    assert extract_reset_seconds(key_obj) == pytest.approx(0.0)
+
+
+def test_extract_reset_seconds_codex_fallback_future_updated_at_no_inflation(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr("src.services.provider.pool.dimensions._helpers.time.time", lambda: 2000.0)
+    key_obj = SimpleNamespace(
+        provider_type="codex",
+        upstream_metadata={
+            "codex": {
+                "primary_reset_seconds": 120.0,
+                "updated_at": 2600.0,
+            }
+        },
+    )
+
+    assert extract_reset_seconds(key_obj) == pytest.approx(120.0)
+
+
 def test_resolve_pool_account_state_keeps_codex_metadata_block() -> None:
     state = resolve_pool_account_state(
         provider_type="codex",