refactor: 调度器迁移至独立模块，消除 services->api 反向依赖

- 将调度器相关模块从 src/services/cache/ 迁移到 src/services/scheduling/
- 下沉类型定义到 core 层: AccessRestrictions, ProviderAuthInfo, ParsedChunk/StreamStats, 视频工具函数
- 提取 thinking_cache 签名缓存到 core/api_format/conversion/
- 提取 provider 认证逻辑到 services/provider/auth
- 提取遥测记录到 services/usage/telemetry
- 提取 models 列表缓存到 services/cache/model_list_cache
- 更新所有引用方的 import 路径及相关测试

src/services/system/cache_warmup.py

@@ -72,7 +72,9 @@ class CacheWarmupService:
         """预热管理员仪表盘统计缓存"""
         db = None
         try:
-            from src.api.dashboard.routes import AdminDashboardStatsAdapter
+            from src.api.dashboard.routes import (  # TODO(arch): 提取 dashboard 统计计算到 services 层
+                AdminDashboardStatsAdapter,
+            )
             from src.models.database import User as DBUser
 
             db = create_session()
@@ -128,7 +130,9 @@ class CacheWarmupService:
         """预热每日统计缓存"""
         db = None
         try:
-            from src.api.dashboard.routes import DashboardDailyStatsAdapter
+            from src.api.dashboard.routes import (  # TODO(arch): 提取 dashboard 统计计算到 services 层
+                DashboardDailyStatsAdapter,
+            )
             from src.models.database import User as DBUser
 
             db = create_session()