chore(prep): shared groundwork for the parallel task batch

多 agent 并行批次的协调提交（消除全部共享文件冲突面）：
- 迁移 0004：id_session + ob_event 两表（T3/T4 用，任务不再写迁移）
- ORM：UserSession / ObEvent；错误码：九个新码（40xxx/60006，含 meta）
- 配置：四档 tiers / refresh TTL / 任务奖励注册表 / 埋点上限 / COS 直传全套
- 骨架：packages/analytics + packages/storage + events/uploads 空路由（已注册）
- deps：AnalyticsServiceDep / StorageServiceDep；DailyBudgetGuard 接收 tiers
- uv add cos-python-sdk-v5；import-linter/CI/Makefile 纳入两个新包

packages/shared/config.py

@@ -106,6 +106,67 @@ class Settings(BaseSettings):
     llm_daily_budget_enabled: bool = True
     llm_daily_budget_cents: Decimal = Decimal("100000")
     llm_budget_timezone_offset_hours: int = 8
+    # 四档分级降级（架构 §13.3，T-P1-25b）。JSON 为列表：
+    # [{"threshold":0.8,"name":"degrade_secondary","blocked":["hd_export"],...}]
+    # blocked 支持 "*"; allow 仅 block_all 档有意义（纯文本对话放行）。
+    llm_budget_tiers: list[dict[str, Any]] = Field(
+        default_factory=lambda: [
+            {"threshold": 0.6, "name": "warn", "blocked": []},
+            {
+                "threshold": 0.8,
+                "name": "degrade_secondary",
+                "blocked": ["hd_export", "report_regen"],
+            },
+            {"threshold": 0.9, "name": "degrade_generation", "blocked": ["hairstyle", "tryon"]},
+            {"threshold": 1.0, "name": "block_all", "blocked": "*", "allow": ["agent_chat"]},
+        ],
+        alias="LLM_BUDGET_TIERS_JSON",
+    )
+
+    # --- Auth: refresh sessions (FR-ACC-05) --------------------------------
+    refresh_token_ttl_seconds: int = 2_592_000  # 30 天
+
+    # --- 任务奖励（FR-BILL-03/04，配置化）-----------------------------------
+    # amount 全部是占位值 1：正式数值待产品在产品方案 §3.2 定稿后改 env，不改代码。
+    # claim_period 决定幂等粒度（同一任务同周期只能领一次）。
+    task_bonus_rules: dict[str, dict[str, Any]] = Field(
+        default_factory=lambda: {
+            "sign_in": {"quota_key": "agent_chat", "amount": 1, "claim_period": "day"},
+            "profile_complete": {
+                "quota_key": "agent_chat",
+                "amount": 1,
+                "claim_period": "lifetime",
+            },
+            "report_feedback": {"quota_key": "report_regen", "amount": 1, "claim_period": "day"},
+            "share_report": {"quota_key": "tryon", "amount": 1, "claim_period": "day"},
+            "invite_friend": {"quota_key": "tryon", "amount": 1, "claim_period": "day"},
+        },
+        alias="TASK_BONUS_RULES_JSON",
+    )
+
+    # --- 客户端埋点（FR-SYS-06）---------------------------------------------
+    events_max_batch: int = 50
+    events_props_max_bytes: int = 8192
+
+    # --- 腾讯云 COS 直传（FR-SYS-03 / T-P1-27）------------------------------
+    cos_region: str = "ap-shanghai"
+    cos_secret_id: str = ""
+    cos_secret_key: str = ""
+    cos_bucket_temp: str = "meida-temp"  # 临时桶，2 小时生命周期（CR-02）
+    cos_bucket_user: str = "meida-user"
+    cos_bucket_kb: str = "meida-kb"
+    cos_bucket_report: str = "meida-report"
+    cos_presign_expire_seconds: int = 600
+    upload_max_bytes: int = 20_971_520  # 20MB
+    upload_allowed_types: str = "image/jpeg,image/png,image/webp"
+    # scene → {"bucket": "temp"|"user"|"kb"|"report"}。新增上传场景只改这里。
+    upload_scenes: dict[str, dict[str, Any]] = Field(
+        default_factory=lambda: {
+            "report_photo": {"bucket": "temp"},
+            "avatar": {"bucket": "temp"},
+        },
+        alias="UPLOAD_SCENES_JSON",
+    )
 
     # --- Observability -----------------------------------------------------
     otel_enabled: bool = False
@@ -118,6 +179,9 @@ class Settings(BaseSettings):
         "llm_cost_rates",
         "llm_cost_rates_peak",
         "llm_default_cost_rate",
+        "llm_budget_tiers",
+        "task_bonus_rules",
+        "upload_scenes",
         mode="before",
     )
     @classmethod