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/main.py

@@ -9,7 +9,7 @@ from pathlib import Path
 
 from .database import engine, get_db, init_db
 from .models import Base
-from .api import topics, system, articles, publishing, auth, admin, audit, optimizer_logs, cases, task_logs, llm_configs, system_configs
+from .api import topics, system, articles, publishing, auth, admin, audit, optimizer_logs, cases, task_logs, llm_configs, system_configs, topic_config, calendar, metrics, assets, tasks, platform_config
 from .initial_data import import_initial_data
 
 app = FastAPI(title="宇之然内容创作平台", version="0.1.0")
@@ -42,6 +42,12 @@ app.include_router(cases.router)
 app.include_router(task_logs.router)
 app.include_router(llm_configs.router)
 app.include_router(system_configs.router)
+app.include_router(topic_config.router)
+app.include_router(calendar.router)
+app.include_router(metrics.router)
+app.include_router(assets.router)
+app.include_router(tasks.router)
+app.include_router(platform_config.router)
 
 # 挂载前端
 FRONTEND_DIR = Path(__file__).parent.parent.parent / "frontend"