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/models/audit_log.py

@@ -0,0 +1,21 @@
+import uuid
+from datetime import datetime
+from sqlalchemy import String, DateTime, func
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.dialects.postgresql import UUID, JSONB
+from app.database import Base
+
+
+class AuditLog(Base):
+    __tablename__ = "audit_logs"
+
+    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    entity_type: Mapped[str] = mapped_column(String(30))
+    entity_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True))
+    entity_name: Mapped[str] = mapped_column(String(200), default="")
+    action: Mapped[str] = mapped_column(String(10))  # create / update / delete
+    operator_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True))
+    operator_name: Mapped[str] = mapped_column(String(50), default="")
+    summary: Mapped[str | None] = mapped_column(String(500), nullable=True)
+    details: Mapped[dict | None] = mapped_column(JSONB, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())

backend/app/models/user.py

@@ -17,4 +17,5 @@ class User(Base):
     wecom_userid: Mapped[str | None] = mapped_column(String(100), unique=True, nullable=True)
     require_report: Mapped[bool] = mapped_column(default=True, server_default="true")
     color: Mapped[str | None] = mapped_column(String(7), nullable=True)  # e.g. "#C62828"
+    theme: Mapped[str] = mapped_column(String(20), default="editorial", server_default="editorial")  # editorial / light
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())

backend/app/models/visit.py

@@ -22,6 +22,7 @@ class Visit(Base):
     companion_names: Mapped[list] = mapped_column(ARRAY(Text), default=list)
     photos: Mapped[list | None] = mapped_column(ARRAY(Text), nullable=True)
     manager_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id"), index=True)
+    visit_group_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), nullable=True, index=True)
     edit_log: Mapped[list] = mapped_column(JSONB, default=list)
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
     updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())