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/daily_notes.py

@@ -10,6 +10,7 @@ from app.models.daily_note import DailyNote
 from app.models.user import User
 from app.schemas.daily_note import DailyNoteCreate, DailyNoteUpdate, DailyNoteOut
 from app.utils.timezone import today_cst, parse_date
+from app.utils.edit_log import compute_diff, append_entry, init_entry
 
 router = APIRouter(prefix="/daily-notes", tags=["DailyNotes"])
 
@@ -20,8 +21,8 @@ async def _enrich(note: DailyNote, db: AsyncSession) -> dict:
         "id": note.id, "manager_id": note.manager_id,
         "note_date": note.note_date, "category": note.category,
         "content": note.content, "time_range": note.time_range,
-        "created_at": note.created_at, "updated_at": note.updated_at,
-        "manager_name": mgr.scalar_one_or_none(),
+        "edit_log": note.edit_log or [], "created_at": note.created_at,
+        "updated_at": note.updated_at, "manager_name": mgr.scalar_one_or_none(),
     }
 
 
@@ -85,6 +86,7 @@ async def create_note(
         content=data.content,
         time_range=data.time_range,
     )
+    init_entry(note, current_user["name"])
     db.add(note)
     await db.commit()
     await db.refresh(note)
@@ -104,11 +106,16 @@ async def update_note(
     if current_user["role"] == "manager" and str(note.manager_id) != current_user["user_id"]:
         raise HTTPException(status_code=403, detail="Access denied")
 
+    old_snapshot = {"note_date": str(note.note_date), "category": note.category, "content": note.content, "time_range": note.time_range}
     update_data = data.model_dump(exclude_unset=True)
     if "note_date" in update_data and update_data["note_date"]:
         update_data["note_date"] = parse_date(update_data["note_date"])
     for k, v in update_data.items():
         setattr(note, k, v)
+    new_snapshot = {"note_date": str(note.note_date), "category": note.category, "content": note.content, "time_range": note.time_range}
+    changes = compute_diff(old_snapshot, new_snapshot)
+    if changes:
+        append_entry(note, current_user["name"], changes, getattr(data, "edit_reason", None))
     await db.commit()
     await db.refresh(note)
     return await _enrich(note, db)