chore(prep): shared groundwork for batch-4 (report pipeline)

第四批（T15 编排/T16 视觉诊断/T17 文案校验）协调提交：
- 迁移 0006：rp_report（result JSONB 按阶段键承载中间态）/rp_input
 （derived_features 视觉中间态）/rp_share（V1 只建结构）
- ORM 三模型；错误码 40420/40920（文案无价格字样）
- 配置：report_pipeline_stages（dotted path 动态装配）+ vision/tier
- packages/report/pipeline.py：Stage Protocol + ReportContext（三任务共同契约，
  动态 import 的动机与代价写在 docstring）
- 路由桩 reports.py 已注册

apps/api/main.py

@@ -12,7 +12,18 @@ from contextlib import asynccontextmanager
 from fastapi import FastAPI
 
 from apps.api.deps import build_llm_gateway
-from apps.api.routers import agent, auth, auth_sms, events, health, kb, quota, tasks, uploads
+from apps.api.routers import (
+    agent,
+    auth,
+    auth_sms,
+    events,
+    health,
+    kb,
+    quota,
+    reports,
+    tasks,
+    uploads,
+)
 from packages.shared.config import Settings, get_settings
 from packages.shared.db import dispose_engine
 from packages.shared.handlers import install_exception_handlers
@@ -78,6 +89,7 @@ def create_app(settings: Settings | None = None) -> FastAPI:
         events.router,
         uploads.router,
         kb.router,
+        reports.router,
     )
     for router in routers:
         app.include_router(router, prefix=cfg.api_prefix)