feat: silent wechat login, marketing tab optimization, admin page foundation

- Add silent WeChat login for MP/browser environments
- Fix Python 3.6 compatibility (remove typing.Annotated usage)
- Marketing page: tab-based content generation with category support
- Translate page: add auto-detect language default
- Homepage: add TTS playback, announcement ticker, remove redundant quick-actions
- Fix FAB button overlap with custom tabbar on customers/quotation pages
- Make openai/anthropic imports lazy for Python 3.6 compat

backend/app/api/v1/followup.py

@@ -1,6 +1,6 @@
 from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.ext.asyncio import AsyncSession
-from typing import Annotated, Optional
+from typing import Optional
 from app.database import get_db
 from app.services.followup_engine import FollowupEngine
 from app.api.v1.deps import get_current_user_id
@@ -11,7 +11,7 @@ router = APIRouter()
 @router.get("/strategies")
 async def list_strategies(
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     engine = FollowupEngine(db)
     await engine.ensure_default_strategies()
@@ -23,7 +23,7 @@ async def get_pending_followups(
     page: int = Query(1, ge=1),
     size: int = Query(20, ge=1, le=100),
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     engine = FollowupEngine(db)
     return await engine.get_pending_followups(user_id, page, size)
@@ -34,7 +34,7 @@ async def get_followup_logs(
     page: int = Query(1, ge=1),
     size: int = Query(20, ge=1, le=100),
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     engine = FollowupEngine(db)
     return await engine.get_followup_logs(user_id, page, size)
@@ -44,7 +44,7 @@ async def get_followup_logs(
 async def mark_followup_sent(
     log_id: str,
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     engine = FollowupEngine(db)
     success = await engine.mark_sent(user_id, log_id)
@@ -58,7 +58,7 @@ async def edit_and_send_followup(
     log_id: str,
     body: dict,
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     edited_text = body.get("edited_text", "")
     if not edited_text:
@@ -73,7 +73,7 @@ async def edit_and_send_followup(
 @router.get("/stats")
 async def get_followup_stats(
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     engine = FollowupEngine(db)
     return await engine.get_stats(user_id)
@@ -82,7 +82,7 @@ async def get_followup_stats(
 @router.post("/scan")
 async def trigger_followup_scan(
     user_id: str = Depends(get_current_user_id),
-    db: Annotated[AsyncSession, Depends(get_db)] = None,
+    db: AsyncSession = Depends(get_db),
 ):
     engine = FollowupEngine(db)
     result = await engine.scan_and_followup()