新增文件管理与技能管理功能：

- **文件管理**：
  - 支持文件上传、解析和删除。
  - 限制支持格式（txt, md, docx, pdf），最大 10MB。
  - 提供前端上传区、文件列表及后端解析服务。

- **技能管理**：
  - 新增技能的创建、更新及删除功能。
  - 支持分配自定义提示词和工具权限。
  - 提供技能列表及分组工具选择交互界面。

同时调整相关 API 和前端组件，优化协作体验。

backend/app/routers/files.py

@@ -0,0 +1,130 @@
+"""文件上传/管理路由"""
+
+import uuid
+from pathlib import Path
+
+from fastapi import APIRouter, HTTPException, UploadFile, File
+from sqlmodel import Session, select
+
+from ..database import engine, DATA_DIR
+from ..models import Novel, NovelFile
+from ..schemas import FileRead, FileList
+from ..services.file_parser import parse_file, ALLOWED_EXTENSIONS, MAX_FILE_SIZE
+
+router = APIRouter(prefix="/api/novels/{novel_id}/files", tags=["files"])
+
+# 上传文件存储根目录
+UPLOAD_DIR = DATA_DIR / "uploads"
+
+
+def _get_novel_upload_dir(novel_id: int) -> Path:
+    """获取小说的上传目录，不存在则创建"""
+    d = UPLOAD_DIR / str(novel_id)
+    d.mkdir(parents=True, exist_ok=True)
+    return d
+
+
+@router.post("", response_model=FileRead, status_code=201)
+async def upload_file(novel_id: int, file: UploadFile = File(...)):
+    """上传文件并解析为纯文本"""
+    with Session(engine) as session:
+        # 校验小说存在
+        novel = session.get(Novel, novel_id)
+        if not novel:
+            raise HTTPException(status_code=404, detail="小说不存在")
+
+    # 校验扩展名
+    if not file.filename:
+        raise HTTPException(status_code=400, detail="缺少文件名")
+    ext = Path(file.filename).suffix.lower()
+    if ext not in ALLOWED_EXTENSIONS:
+        raise HTTPException(
+            status_code=400,
+            detail=f"不支持的文件格式 {ext}，仅支持: {', '.join(sorted(ALLOWED_EXTENSIONS))}",
+        )
+
+    # 读取文件内容
+    content = await file.read()
+    file_size = len(content)
+
+    if file_size > MAX_FILE_SIZE:
+        raise HTTPException(
+            status_code=400,
+            detail=f"文件过大（{file_size / 1024 / 1024:.1f}MB），最大允许 10MB",
+        )
+
+    # 生成存储名并保存原始文件
+    stored_name = f"{uuid.uuid4().hex}{ext}"
+    upload_dir = _get_novel_upload_dir(novel_id)
+    file_path = upload_dir / stored_name
+    file_path.write_bytes(content)
+
+    # 解析纯文本
+    try:
+        text_content = parse_file(file_path, file.content_type or "")
+    except Exception as e:
+        # 解析失败，清理已保存的文件
+        file_path.unlink(missing_ok=True)
+        raise HTTPException(status_code=400, detail=f"文件解析失败: {e}")
+
+    # 保存纯文本缓存
+    text_path = upload_dir / f"{stored_name}.txt"
+    text_path.write_text(text_content, encoding="utf-8")
+
+    # 写入数据库
+    with Session(engine) as session:
+        novel_file = NovelFile(
+            novel_id=novel_id,
+            filename=file.filename,
+            stored_name=stored_name,
+            file_size=file_size,
+            mime_type=file.content_type or "",
+            text_length=len(text_content),
+        )
+        session.add(novel_file)
+        session.commit()
+        session.refresh(novel_file)
+        return novel_file
+
+
+@router.get("", response_model=FileList)
+def list_files(novel_id: int):
+    """列出小说关联的所有文件"""
+    with Session(engine) as session:
+        stmt = (
+            select(NovelFile)
+            .where(NovelFile.novel_id == novel_id)
+            .order_by(NovelFile.created_at.desc())
+        )
+        files = session.exec(stmt).all()
+        items = [
+            FileRead(
+                id=f.id,  # type: ignore
+                novel_id=f.novel_id,
+                filename=f.filename,
+                file_size=f.file_size,
+                mime_type=f.mime_type,
+                text_length=f.text_length,
+                created_at=f.created_at,
+            )
+            for f in files
+        ]
+        return FileList(items=items, total=len(items))
+
+
+@router.delete("/{file_id}", status_code=204)
+def delete_file(novel_id: int, file_id: int):
+    """删除文件（数据库记录 + 磁盘文件）"""
+    with Session(engine) as session:
+        novel_file = session.get(NovelFile, file_id)
+        if not novel_file or novel_file.novel_id != novel_id:
+            raise HTTPException(status_code=404, detail="文件不存在")
+
+        # 删除磁盘文件
+        upload_dir = _get_novel_upload_dir(novel_id)
+        (upload_dir / novel_file.stored_name).unlink(missing_ok=True)
+        (upload_dir / f"{novel_file.stored_name}.txt").unlink(missing_ok=True)
+
+        # 删除数据库记录
+        session.delete(novel_file)
+        session.commit()