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/platform_config.py

@@ -0,0 +1,68 @@
+from fastapi import APIRouter, Depends, HTTPException, Query
+from sqlalchemy.orm import Session
+from typing import List, Optional
+
+from ..database import get_db
+from ..models import PlatformConfig
+from ..schemas import PlatformConfigCreate, PlatformConfigUpdate, PlatformConfigResponse
+from .auth import get_current_user
+
+router = APIRouter(prefix="/api/platform-config", tags=["platform-config"])
+
+
+@router.get("", response_model=List[PlatformConfigResponse])
+def list_platforms(
+    active_only: bool = True,
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    query = db.query(PlatformConfig)
+    if active_only:
+        query = query.filter(PlatformConfig.is_active == True)
+    return query.order_by(PlatformConfig.id).all()
+
+
+@router.post("", response_model=PlatformConfigResponse)
+def create_platform(
+    data: PlatformConfigCreate,
+    db: Session = Depends(get_db),
+    current_user=Depends(get_current_user)
+):
+    existing = db.query(PlatformConfig).filter(PlatformConfig.platform == data.platform).first()
+    if existing:
+        raise HTTPException(status_code=400, detail=f"平台 '{data.platform}' 已存在")
+    p = PlatformConfig(**data.model_dump())
+    db.add(p)
+    db.commit()
+    db.refresh(p)
+    return p
+
+
+@router.get("/{platform}", response_model=PlatformConfigResponse)
+def get_platform(platform: str, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
+    p = db.query(PlatformConfig).filter(PlatformConfig.platform == platform).first()
+    if not p:
+        raise HTTPException(status_code=404, detail="平台不存在")
+    return p
+
+
+@router.put("/{platform}", response_model=PlatformConfigResponse)
+def update_platform(platform: str, data: PlatformConfigUpdate, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
+    p = db.query(PlatformConfig).filter(PlatformConfig.platform == platform).first()
+    if not p:
+        raise HTTPException(status_code=404, detail="平台不存在")
+    for k, v in data.model_dump(exclude_unset=True).items():
+        setattr(p, k, v)
+    db.commit()
+    db.refresh(p)
+    return p
+
+
+@router.delete("/{platform}")
+def delete_platform(platform: str, db: Session = Depends(get_db), current_user=Depends(get_current_user)):
+    p = db.query(PlatformConfig).filter(PlatformConfig.platform == platform).first()
+    if not p:
+        raise HTTPException(status_code=404, detail="平台不存在")
+    p.is_active = False
+    db.commit()
+    return {"ok": True}