feat: 操作日志系统 + 日期修复 + 协同去重 + 主题持久化 + 计划自动完成

本次累积提交包含以下功能：

1. 修复：el-date-picker 缺失 value-format 导致日期保存偏移（8处）
2. 新增：协同拜访 visit_group_id 去重机制（完整副本 + 周报合并 + 亮灯去重）
3. 新增：计划自动完成（创建计划检测已有拜访 / 编辑拜访触发）
4. 新增：拜访表单选择客户后自动预填过期计划内容
5. 新增：移动端主题切换按钮 + 后端持久化
6. 新增：操作日志系统 (audit_logs)，全覆盖 8 个模块 CRUD
7. 新增：PC端「我的数据」支局长/领导视角客户经理列

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

backend/app/api/audit.py

@@ -0,0 +1,80 @@
+import uuid
+from typing import Optional
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select, func
+from app.database import get_db
+from app.middleware.auth import get_current_user
+from app.models.audit_log import AuditLog
+
+router = APIRouter(prefix="/audit-logs", tags=["AuditLogs"])
+
+ENTITY_LABELS: dict[str, str] = {
+    "customer": "客户",
+    "visit": "拜访记录",
+    "daily_note": "今日纪要",
+    "work_plan": "工作计划",
+    "mini_business": "小微商机",
+    "key_visit": "要客拜访",
+    "user": "用户",
+    "leave": "请假",
+}
+
+
+@router.get("/")
+async def list_audit_logs(
+    entity_type: Optional[str] = Query(None),
+    action: Optional[str] = Query(None),
+    operator_id: Optional[str] = Query(None),
+    date_from: Optional[str] = Query(None),
+    date_to: Optional[str] = Query(None),
+    page: int = Query(1, ge=1),
+    page_size: int = Query(50, ge=10, le=200),
+    current_user: dict = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """List audit logs. Only director/leader can access."""
+    if current_user["role"] not in ("director", "leader"):
+        return {"items": [], "total": 0}
+
+    base = select(AuditLog)
+    count_q = select(func.count(AuditLog.id))
+
+    if entity_type:
+        base = base.where(AuditLog.entity_type == entity_type)
+        count_q = count_q.where(AuditLog.entity_type == entity_type)
+    if action:
+        base = base.where(AuditLog.action == action)
+        count_q = count_q.where(AuditLog.action == action)
+    if operator_id:
+        base = base.where(AuditLog.operator_id == uuid.UUID(operator_id))
+        count_q = count_q.where(AuditLog.operator_id == uuid.UUID(operator_id))
+    if date_from:
+        base = base.where(AuditLog.created_at >= date_from)
+        count_q = count_q.where(AuditLog.created_at >= date_from)
+    if date_to:
+        base = base.where(AuditLog.created_at < date_to + "T23:59:59")
+        count_q = count_q.where(AuditLog.created_at < date_to + "T23:59:59")
+
+    total = (await db.execute(count_q)).scalar() or 0
+
+    query = base.order_by(AuditLog.created_at.desc()).offset((page - 1) * page_size).limit(page_size)
+    rows = (await db.execute(query)).scalars().all()
+
+    items = []
+    for r in rows:
+        items.append({
+            "id": str(r.id),
+            "entity_type": r.entity_type,
+            "entity_type_label": ENTITY_LABELS.get(r.entity_type, r.entity_type),
+            "entity_id": str(r.entity_id),
+            "entity_name": r.entity_name,
+            "action": r.action,
+            "operator_id": str(r.operator_id),
+            "operator_name": r.operator_name,
+            "summary": r.summary or "",
+            "details": r.details,
+            "created_at": str(r.created_at),
+        })
+
+    return {"items": items, "total": total}