feat: 信息架构重组 + 变更追踪 + 图片预览增强

- 信息架构重组: 周报精简为拜访+纪要两个Tab，工作计划/商机/要客独立为侧边栏「工作」分组下的独立页面
- 侧边栏分组: 汇总/工作/管理三层分组，仪表盘四卡可点击跳转
- 变更追踪(edit_log): 5张表新增JSONB edit_log列，POST创建/PUT diff自动记录，编辑弹窗变更时间轴，表格🕐编辑标记
- 图片预览增强: ImagePreview统一组件，支持适应页面/缩放/拖拽平移/滚轮缩放/键盘快捷键
- 修复客户导入500错误(errors变量未初始化)
- 移除工作计划/商机/要客页面冗余编辑按钮

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

backend/app/api/mini_business.py

@@ -9,6 +9,7 @@ from app.models.mini_business import MiniBusiness
 from app.models.customer import Customer
 from app.models.user import User
 from app.schemas.mini_business import MiniBusinessCreate, MiniBusinessUpdate, MiniBusinessOut
+from app.utils.edit_log import compute_diff, append_entry, init_entry
 
 router = APIRouter(prefix="/mini-business", tags=["MiniBusiness"])
 
@@ -26,6 +27,7 @@ async def _enrich(m: MiniBusiness, db: AsyncSession) -> dict:
         "status": m.status,
         "manager_id": str(m.manager_id),
         "manager_name": mgr.scalar_one_or_none(),
+        "edit_log": m.edit_log or [],
         "expected_revenue_date": m.expected_revenue_date,
     }
 
@@ -61,6 +63,7 @@ async def create_mini_business(
         manager_id=uuid.UUID(current_user["user_id"]),
         expected_revenue_date=data.expected_revenue_date,
     )
+    init_entry(m, current_user["name"])
     db.add(m)
     await db.commit()
     await db.refresh(m)
@@ -80,9 +83,14 @@ async def update_mini_business(
     if current_user["role"] == "manager" and str(m.manager_id) != current_user["user_id"]:
         raise HTTPException(status_code=403, detail="Access denied")
 
+    old_snapshot = {"customer_id": str(m.customer_id), "product_type": m.product_type, "amount": m.amount, "follow_up_detail": m.follow_up_detail, "status": m.status, "expected_revenue_date": m.expected_revenue_date}
     update_data = data.model_dump(exclude_unset=True)
     for k, v in update_data.items():
         setattr(m, k, v)
+    new_snapshot = {"customer_id": str(m.customer_id), "product_type": m.product_type, "amount": m.amount, "follow_up_detail": m.follow_up_detail, "status": m.status, "expected_revenue_date": m.expected_revenue_date}
+    changes = compute_diff(old_snapshot, new_snapshot)
+    if changes:
+        append_entry(m, current_user["name"], changes, getattr(data, "edit_reason", None))
     await db.commit()
     await db.refresh(m)
     return await _enrich(m, db)