feat: migrate ORM base to sqlmodel-ext, add file viewers and WOPI integration

- Migrate SQLModel base classes, mixins, and database management to
  external sqlmodel-ext package; remove sqlmodels/base/, sqlmodels/mixin/,
  and sqlmodels/database.py
- Add file viewer/editor system with WOPI protocol support for
  collaborative editing (OnlyOffice, Collabora)
- Add enterprise edition license verification module (ee/)
- Add Dockerfile multi-stage build with Cython compilation support
- Add new dependencies: sqlmodel-ext, cryptography, whatthepatch

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main.py

@@ -1,16 +1,40 @@
+from pathlib import Path
 from typing import NoReturn
 
 from fastapi import FastAPI, Request
+from loguru import logger as l
 
-from utils.conf import appmeta
-from utils.http.http_exceptions import raise_internal_error
-from utils.lifespan import lifespan
+from routers import router
+from service.redis import RedisManager
 from sqlmodels.database_connection import DatabaseManager
 from sqlmodels.migration import migration
 from utils import JWT
-from routers import router
-from service.redis import RedisManager
-from loguru import logger as l
+from utils.conf import appmeta
+from utils.http.http_exceptions import raise_internal_error
+from utils.lifespan import lifespan
+
+# 尝试加载企业版功能
+try:
+    from ee import init_ee
+    from ee.license import LicenseError
+
+    async def _init_ee_and_routes() -> None:
+        try:
+            await init_ee()
+        except LicenseError as exc:
+            l.critical(f"许可证验证失败: {exc}")
+            raise SystemExit(1) from exc
+
+        from ee.routers import ee_router
+        from routers.api.v1 import router as v1_router
+        v1_router.include_router(ee_router)
+
+    lifespan.add_startup(_init_ee_and_routes)
+except ImportError:
+    l.info("以 Community 版本运行")
+
+STATICS_DIR: Path = (Path(__file__).parent / "statics").resolve()
+"""前端静态文件目录（由 Docker 构建时复制）"""
 
 async def _init_db() -> None:
     """初始化数据库连接引擎"""
@@ -64,6 +88,31 @@ async def handle_unexpected_exceptions(
 # 挂载路由
 app.include_router(router)
 
+# 挂载前端静态文件（仅当 statics/ 目录存在时，即 Docker 部署环境）
+if STATICS_DIR.is_dir():
+    from starlette.staticfiles import StaticFiles
+    from fastapi.responses import FileResponse
+
+    _assets_dir: Path = STATICS_DIR / "assets"
+    if _assets_dir.is_dir():
+        app.mount("/assets", StaticFiles(directory=_assets_dir), name="assets")
+
+    @app.get("/{path:path}")
+    async def spa_fallback(path: str) -> FileResponse:
+        """
+        SPA fallback 路由
+
+        优先级：API 路由 > /assets 静态挂载 > 此 catch-all 路由。
+        若请求路径对应 statics/ 下的真实文件则直接返回，否则返回 index.html。
+        """
+        file_path: Path = (STATICS_DIR / path).resolve()
+        # 防止路径穿越
+        if file_path.is_relative_to(STATICS_DIR) and path and file_path.is_file():
+            return FileResponse(file_path)
+        return FileResponse(STATICS_DIR / "index.html")
+
+    l.info(f"前端静态文件已挂载: {STATICS_DIR}")
+
 # 防止直接运行 main.py
 if __name__ == "__main__":
     l.error("请用 fastapi ['dev', 'run'] 命令启动服务")