feat: 完成布局优化 - 操作列固定、批量按钮自适应、分类标签带数量

优化内容:
1. 表格布局:
   - 使用 calc(100vw - 160px) 确保表格不超出视口
   - 操作列 fixed='right' 固定在右侧，宽度 300px
   - 按钮 3 个后自动换行 (max-width: 200px)
   - 恢复合理列宽，不再过度压缩

2. 批量操作区域:
   - 容器改为 inline-block，宽度自适应按钮内容
   - 背景宽度与按钮总宽度匹配

3. 分类标签:
   - 显示数量 (如 '待处理 (20)')
   - 点击切换筛选，去掉误导的 'X' 图标

4. 删除功能:
   - 操作列增加删除按钮
   - 删除前弹出确认对话框

5. 系统日志:
   - 修复后端日志路径 (parents[4])
   - 404 时显示友好提示

6. 其他:
   - 左侧菜单宽度 160px
   - 所有功能保留 (登录、用户管理、批量操作等)

platform/backend/app/api/publishing.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+"""发布管理 API"""
+from fastapi import APIRouter, HTTPException, Depends, Request
+from pydantic import BaseModel
+from datetime import datetime
+from typing import Optional
+
+from app.database import get_db
+from app.models import Topic, PublishRecord, User
+from sqlalchemy.orm import Session
+from .auth import verify_token
+from ..core.audit_logger import audit_log
+
+router = APIRouter()
+
+class PublishRequest(BaseModel):
+    topic_id: str
+
+class PublishResponse(BaseModel):
+    ok: bool
+    topic_id: str
+    message: str
+
+def get_current_user(request: Request, db: Session = Depends(get_db)) -> User:
+    """获取当前登录用户（可选，未登录也允许，但记录为 anonymous）"""
+    auth_header = request.headers.get("Authorization")
+    if not auth_header or not auth_header.startswith("Bearer "):
+        return None
+    token = auth_header.split(" ")[1]
+    try:
+        from .auth import verify_token
+        return verify_token(token, db)
+    except Exception:
+        return None
+
+@router.post("/api/publishing/create", response_model=PublishResponse)
+async def create_publish_record(
+    req: PublishRequest,
+    request: Request,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    """标记选题为已发布，并创建发布记录"""
+    try:
+        # 查找选题
+        topic = db.query(Topic).filter(Topic.id == req.topic_id).first()
+        if not topic:
+            raise HTTPException(status_code=404, detail=f"选题 {req.topic_id} 不存在")
+
+        if topic.status != '待发布':
+            raise HTTPException(status_code=400, detail=f"选题 {req.topic_id} 状态不是待发布")
+
+        # 更新选题状态
+        topic.status = '已发布'
+        topic.updated_at = datetime.now()
+        topic.published_at = datetime.now().date()  # 设置发布时间为今天
+
+        # 创建发布记录
+        operator = current_user.username if current_user else 'anonymous'
+        record = PublishRecord(
+            topic_id=req.topic_id,
+            platform='all',
+            action='publish',
+            status='success',
+            operator=operator,
+            description=f"选题 {req.topic_id} 已发布"
+        )
+        db.add(record)
+        db.commit()
+        # 强制刷新会话缓存，确保后续读取最新数据
+        db.expire_all()
+        db.refresh(topic)
+
+        # 审计日志
+        audit_log(
+            action="publish",
+            user=current_user,
+            resource_type="topic",
+            resource_id=req.topic_id,
+            details={"operator": operator, "status": "success"},
+            ip_address=request.client.host if request.client else None,
+            user_agent=request.headers.get("user-agent", ""),
+            db=db
+        )
+
+        return PublishResponse(
+            ok=True,
+            topic_id=req.topic_id,
+            message=f"选题 {req.topic_id} 已成功发布"
+        )
+    except HTTPException:
+        raise
+    except Exception as e:
+        db.rollback()
+        raise HTTPException(status_code=500, detail=str(e))