feat: 5个列表API新增搜索参数支持

- visits: search沟通内容/客户需求/拜访人/客户名
- daily_notes: search内容
- work_plans: search计划内容/客户名
- mini_business: search产品/跟进/客户名
- key_visits: search描述/拜访人/客户名

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/api/daily_notes.py

@@ -30,6 +30,7 @@ async def _enrich(note: DailyNote, db: AsyncSession) -> dict:
 async def list_notes(
     date_from: Optional[str] = Query(None),
     date_to: Optional[str] = Query(None),
+    search: Optional[str] = Query(None),
     current_user: dict = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
@@ -40,6 +41,8 @@ async def list_notes(
         query = query.where(DailyNote.note_date >= parse_date(date_from))
     if date_to:
         query = query.where(DailyNote.note_date <= parse_date(date_to))
+    if search:
+        query = query.where(DailyNote.content.ilike(f"%{search}%"))
     query = query.order_by(DailyNote.note_date.desc(), DailyNote.created_at.desc()).limit(100)
     result = await db.execute(query)
     return [await _enrich(n, db) for n in result.scalars().all()]