feat(api): implement FastAPI routes with JWT authentication

- jokes.py: Public joke listing, detail, and random endpoints
- categories.py: Type and crowd listing endpoints
- auth.py: Login endpoint with JWT token generation
- admin.py: Full CRUD for jokes, types, crowds with JWT protection
- Fix request body schemas to use Create DTOs instead of Response models

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

api/app/routers/categories.py

@@ -0,0 +1,22 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app.models.category import JokeCrowd, JokeType
+from app.schemas.category import JokeCrowdResponse, JokeTypeResponse
+
+router = APIRouter(prefix="/categories", tags=["分类"])
+
+
+@router.get("/types", response_model=list[JokeTypeResponse])
+def list_types(db: Session = Depends(get_db)):
+    """获取所有笑话类型"""
+    types = db.query(JokeType).order_by(JokeType.sort_order, JokeType.id).all()
+    return [JokeTypeResponse.model_validate(t) for t in types]
+
+
+@router.get("/crowds", response_model=list[JokeCrowdResponse])
+def list_crowds(db: Session = Depends(get_db)):
+    """获取所有笑话人群分类"""
+    crowds = db.query(JokeCrowd).order_by(JokeCrowd.sort_order, JokeCrowd.id).all()
+    return [JokeCrowdResponse.model_validate(c) for c in crowds]