feat: 全面升级项目架构 - PostgreSQL迁移 + 配置化改造

主要变更:
- 数据库: SQLite → PostgreSQL (yzr_nr)
- 选题系统: 硬编码字段 → 配置化 (TopicField/TopicConfigField/TopicStatusConfig)
- 新增模型: ContentCalendar, ContentMetrics, MediaAsset, PlatformConfig, ContentTask
- 新增 API: topic-config, calendar, metrics, assets, tasks, platform-config
- 数据迁移: 现有选题数据迁移到新 schema (field_id/tags/custom_data/scoring_data)
- 初始化数据: 10个领域, 5种状态, 3个平台配置

服务运行: http://localhost:8001
默认账号: admin / admin123

platform/backend/app/api/assets.py

@@ -0,0 +1,180 @@
+import os
+import uuid
+import hashlib
+from pathlib import Path
+from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Query
+from sqlalchemy.orm import Session
+from typing import List, Optional
+
+from ..database import get_db
+from ..models import MediaAsset
+from ..schemas import MediaAssetCreate, MediaAssetUpdate, MediaAssetResponse
+from .auth import get_current_user
+
+router = APIRouter(prefix="/api/assets", tags=["assets"])
+
+PROJECT_ROOT = Path(__file__).resolve().parents[4]
+if os.getenv('PROJECT_ROOT'):
+    PROJECT_ROOT = Path(os.getenv('PROJECT_ROOT'))
+UPLOAD_DIR = PROJECT_ROOT / "content" / "images"
+ALLOWED_IMAGE_TYPES = {"image/jpeg", "image/png", "image/gif", "image/webp", "image/svg+xml"}
+
+
+@router.get("", response_model=List[MediaAssetResponse])
+def list_assets(
+    file_type: Optional[str] = None,
+    tag: Optional[str] = None,
+    topic_id: Optional[str] = None,
+    search: Optional[str] = None,
+    limit: int = Query(50, le=200),
+    offset: int = Query(0, ge=0),
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    query = db.query(MediaAsset)
+
+    if file_type:
+        query = query.filter(MediaAsset.file_type == file_type)
+    if tag:
+        query = query.filter(MediaAsset.tags.contains([tag]))
+    if topic_id:
+        query = query.filter(MediaAsset.topic_ids.contains([topic_id]))
+    if search:
+        query = query.filter(
+            (MediaAsset.filename.contains(search)) |
+            (MediaAsset.alt_text.contains(search))
+        )
+
+    return query.order_by(MediaAsset.created_at.desc()).offset(offset).limit(limit).all()
+
+
+@router.get("/tags")
+def list_tags(
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    assets = db.query(MediaAsset.tags).all()
+    all_tags = set()
+    for a in assets:
+        if a[0]:
+            all_tags.update(a[0])
+    return sorted(all_tags)
+
+
+@router.get("/counts")
+def get_counts(
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    total = db.query(MediaAsset).count()
+    by_type = {}
+    rows = db.query(MediaAsset.file_type, db.func.count(MediaAsset.id)).group_by(MediaAsset.file_type).all()
+    for ftype, cnt in rows:
+        by_type[ftype] = cnt
+    return {"total": total, "by_type": by_type}
+
+
+@router.post("/upload", response_model=MediaAssetResponse)
+async def upload_asset(
+    file: UploadFile = File(...),
+    tags: Optional[str] = Query(None, description="逗号分隔的标签"),
+    alt_text: Optional[str] = Query(None),
+    topic_ids: Optional[str] = Query(None, description="逗号分隔的选题ID"),
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    if file.content_type not in ALLOWED_IMAGE_TYPES:
+        raise HTTPException(status_code=400, detail=f"不支持的文件类型: {file.content_type}")
+
+    UPLOAD_DIR.mkdir(parents=True, exist_ok=True)
+
+    suffix = Path(file.filename).suffix or ""
+    unique_name = f"{uuid.uuid4().hex[:12]}{suffix}"
+    file_path = UPLOAD_DIR / unique_name
+
+    content = await file.read()
+    file_size = len(content)
+
+    with open(file_path, "wb") as f:
+        f.write(content)
+
+    file_type = file.content_type.split("/")[0]
+    if file_type not in ("image", "video", "application"):
+        if suffix in (".pdf", ".doc", ".docx", ".ppt", ".pptx"):
+            file_type = "document"
+        elif suffix in (".mp4", ".mov", ".avi"):
+            file_type = "video"
+        else:
+            file_type = "image"
+
+    parsed_tags = [t.strip() for t in tags.split(",")] if tags else []
+    parsed_topic_ids = [t.strip() for t in topic_ids.split(",")] if topic_ids else []
+
+    asset = MediaAsset(
+        filename=file.filename,
+        file_path=str(file_path),
+        file_type=file_type,
+        mime_type=file.content_type,
+        size=file_size,
+        alt_text=alt_text,
+        tags=parsed_tags,
+        topic_ids=parsed_topic_ids,
+        uploaded_by=current_user.username
+    )
+    db.add(asset)
+    db.commit()
+    db.refresh(asset)
+    return asset
+
+
+@router.put("/{asset_id}", response_model=MediaAssetResponse)
+def update_asset(
+    asset_id: int,
+    data: MediaAssetUpdate,
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    asset = db.query(MediaAsset).filter(MediaAsset.id == asset_id).first()
+    if not asset:
+        raise HTTPException(status_code=404, detail="素材不存在")
+
+    for k, v in data.model_dump(exclude_unset=True).items():
+        setattr(asset, k, v)
+    db.commit()
+    db.refresh(asset)
+    return asset
+
+
+@router.delete("/{asset_id}")
+def delete_asset(
+    asset_id: int,
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    asset = db.query(MediaAsset).filter(MediaAsset.id == asset_id).first()
+    if not asset:
+        raise HTTPException(status_code=404, detail="素材不存在")
+
+    if os.path.exists(asset.file_path):
+        try:
+            os.remove(asset.file_path)
+        except OSError:
+            pass
+
+    db.delete(asset)
+    db.commit()
+    return {"ok": True}
+
+
+@router.post("/{asset_id}/use")
+def increment_usage(
+    asset_id: int,
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    asset = db.query(MediaAsset).filter(MediaAsset.id == asset_id).first()
+    if not asset:
+        raise HTTPException(status_code=404, detail="素材不存在")
+    asset.usage_count = (asset.usage_count or 0) + 1
+    db.commit()
+    return {"ok": True, "usage_count": asset.usage_count}