feat: add user role system and public joke submission API

- Add AdminUser role field (admin/submitter)
- User management in admin panel
- Public joke submission API (no auth required)
- Document submission methods for external workers

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/app/routers/submit.py

@@ -0,0 +1,62 @@
+"""
+公开提交流程 - 供外部用户（submitter）使用。
+无后台管理权限，仅能提交笑话到 pending 状态。
+"""
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+from pydantic import BaseModel
+
+from app.database import get_db
+from app.models.joke import Joke
+
+router = APIRouter(tags=["笑话提交"])
+
+
+class JokeSubmit(BaseModel):
+    """笑话提交"""
+    title: str
+    content: str
+
+
+class JokeBatchSubmit(BaseModel):
+    """批量提交"""
+    jokes: list[JokeSubmit]
+
+
+@router.post("/submit", response_model=dict)
+def submit_joke(data: JokeSubmit, db: Session = Depends(get_db)):
+    """公开接口：提交单条笑话（自动进入待审核状态）"""
+    joke = Joke(
+        title=data.title,
+        content=data.content,
+        status="pending",
+    )
+    db.add(joke)
+    db.commit()
+    db.refresh(joke)
+    return {
+        "success": True,
+        "id": joke.id,
+        "message": f"已提交，ID: {joke.id}"
+    }
+
+
+@router.post("/submit/batch", response_model=dict)
+def submit_jokes_batch(data: JokeBatchSubmit, db: Session = Depends(get_db)):
+    """公开接口：批量提交笑话"""
+    added = []
+    for item in data.jokes:
+        joke = Joke(
+            title=item.title,
+            content=item.content,
+            status="pending",
+        )
+        db.add(joke)
+        added.append(item.title)
+
+    db.commit()
+    return {
+        "success": True,
+        "count": len(added),
+        "message": f"已提交 {len(added)} 条笑话"
+    }