feat(codex): 增强 OAuth 导入解析与账号信息提取，优化维护调度器线程模型

Codex OAuth:
- 导入解析支持附加账号字段（account_id/plan_type/user_id/email）
- enrich_codex 扩展从 access_token 和直接字段提取账号信息
- parse_codex_id_token 支持 JWT/JSON 字符串/dict 三种输入格式
- request patching 新增 openai:compact 格式支持
- codex_usage_parser 新增 credits_unlimited 字段解析

维护调度器:
- 同步 DB 操作迁移到线程池执行，避免阻塞事件循环
- 新增 request_candidates 定期清理任务
- 新增每周 VACUUM ANALYZE 数据库表维护任务
- 新增 enable_db_maintenance 配置项

前端:
- ElapsedTimeText 从 setInterval 改为 requestAnimationFrame
- 时间线过滤 available/unused 占位记录
- Usage 页面默认关闭全局自动刷新
- 移除号池管理中的配额更新时间显示

tests/unit/test_provider_oauth_import_parser.py

@@ -0,0 +1,45 @@
+from __future__ import annotations
+
+from src.api.admin import provider_oauth as module
+
+
+def test_parse_standard_oauth_import_entries_keeps_codex_hints() -> None:
+    entries = module._parse_standard_oauth_import_entries(
+        '[{"refresh_token":"rt_1","accountId":"acc-1","planType":"TEAM","userId":"u-1","email":"u@example.com"}]'
+    )
+
+    assert entries == [
+        {
+            "refresh_token": "rt_1",
+            "account_id": "acc-1",
+            "plan_type": "team",
+            "user_id": "u-1",
+            "email": "u@example.com",
+        }
+    ]
+
+
+def test_parse_tokens_input_compatibility_wrapper() -> None:
+    tokens = module._parse_tokens_input("token_a\ntoken_b")
+    assert tokens == ["token_a", "token_b"]
+
+
+def test_apply_codex_import_hints_only_fills_missing_fields() -> None:
+    auth_config = {
+        "account_id": "existing-account",
+        "plan_type": "",
+    }
+    module._apply_codex_import_hints(
+        auth_config,
+        {
+            "account_id": "acc-1",
+            "plan_type": "plus",
+            "user_id": "user-1",
+            "email": "u@example.com",
+        },
+    )
+
+    assert auth_config["account_id"] == "existing-account"
+    assert auth_config["plan_type"] == "plus"
+    assert auth_config["user_id"] == "user-1"
+    assert auth_config["email"] == "u@example.com"