重大重构：引擎模块拆分 + P0插件实现 + 55个Bug修复

核心变更:
- engine.py(1781行)拆分为8个独立模块: lifecycle/security/deps/
  datastore/pl_injector/watcher/signature/manager
- 新增plugin-bridge: 事件总线 + 服务注册 + RPC通信
- 新增i18n: 国际化/多语言翻译支持
- 新增plugin-storage: 插件键值/文件存储
- 新增ws-api: WebSocket实时通信(pub/sub + 自定义处理器)
- nodejs-adapter统一为Plugin ABC模式

Bug修复:
- 修复load_all()中store_dir未定义崩溃
- 修复DependencyResolver入度计算(拓扑排序)
- 修复PermissionError隐藏内置异常
- 修复CORS中间件头部未附加到响应
- 修复IntegrityChecker跳过__pycache__目录
- 修复版本号不一致(v2.0.0→v1.2.0)
- 修复测试文件的Logger导入/路径/私有方法调用
- 修复context.py缺少typing导入
- 修复config.py STORE_DIR默认路径(./mods→./store)

测试覆盖: 14→91个测试, 全部通过

oss/core/watcher.py

@@ -0,0 +1,65 @@
+import threading
+import time
+from pathlib import Path
+from typing import Callable
+
+from oss.logger.logger import Log
+
+
+class HotReloadError(Exception):
+    pass
+
+
+class FileWatcher:
+    def __init__(self, watch_dirs, extensions, callback):
+        self.watch_dirs = watch_dirs
+        self.extensions = extensions
+        self.callback = callback
+        self._running = False
+        self._thread = None
+        self._file_times = {}
+        self._init_file_times()
+
+    def _init_file_times(self):
+        for watch_dir in self.watch_dirs:
+            p = Path(watch_dir)
+            if p.exists():
+                for f in p.rglob("*"):
+                    if f.is_file() and f.suffix in self.extensions:
+                        self._file_times[str(f)] = f.stat().st_mtime
+
+    def start(self):
+        self._running = True
+        self._thread = threading.Thread(target=self._watch_loop, daemon=True)
+        self._thread.start()
+        Log.info("Core", "文件监控已启动")
+
+    def stop(self):
+        self._running = False
+        if self._thread:
+            self._thread.join(timeout=5)
+
+    def _watch_loop(self):
+        """监控文件变化，触发热重载回调"""
+        while self._running:
+            try:
+                for watch_dir in self.watch_dirs:
+                    p = Path(watch_dir)
+                    if not p.exists():
+                        continue
+                    for f in p.rglob("*"):
+                        if not f.is_file() or f.suffix not in self.extensions:
+                            continue
+                        current_mtime = f.stat().st_mtime
+                        last_mtime = self._file_times.get(str(f))
+                        if last_mtime is not None and current_mtime > last_mtime:
+                            self._file_times[str(f)] = current_mtime
+                            try:
+                                self.callback(str(f))
+                            except Exception as e:
+                                Log.error("Core", f"热重载回调执行失败: {e}")
+                        elif last_mtime is None:
+                            self._file_times[str(f)] = current_mtime
+            except Exception as e:
+                Log.error("Core", f"文件监控异常: {e}")
+            time.sleep(2)