fix(database): improve web environment database connection handling

- Add pre-open check for web to release potentially stale OPFS handles
- Unify close logic across platforms instead of skipping for web
- Add proper logging for connection lifecycle operations
- Remove obsolete error check for "cannot create file" during retries

src/services/database.ts

@@ -53,6 +53,17 @@ async function withMutex<T>(fn: () => Promise<T>): Promise<T> {
 async function openDatabaseWithRetry(dbName: string, maxRetries: number = 3): Promise<SQLite.SQLiteDatabase> {
   const isWeb = typeof window !== 'undefined';
   
+  if (isWeb) {
+    try {
+      const tempDb = await SQLite.openDatabaseAsync(dbName);
+      await tempDb.closeAsync();
+      console.log('[Database] Web: 预打开成功，已释放可能残留的句柄');
+    } catch (e) {
+      console.warn('[Database] Web: 预打开失败:', String(e));
+    }
+    await new Promise(r => setTimeout(r, 50));
+  }
+  
   for (let attempt = 0; attempt <= maxRetries; attempt++) {
     try {
       const database = await SQLite.openDatabaseAsync(dbName);
@@ -66,7 +77,7 @@ async function openDatabaseWithRetry(dbName: string, maxRetries: number = 3): Pr
         console.warn(`[Database] ${delay}ms 后重试...`);
         await new Promise(r => setTimeout(r, delay));
         
-        if (msg.includes('Invalid VFS state') || msg.includes('cannot create file')) {
+        if (msg.includes('Invalid VFS state')) {
           try {
             await SQLite.deleteDatabaseAsync(dbName);
             console.warn('[Database] 已删除损坏的数据库文件');
@@ -237,20 +248,19 @@ export const initDatabase = async (userId?: string): Promise<void> => {
     const isWeb = typeof window !== 'undefined';
     
     if (db) {
-      if (isWeb) {
+      console.log(`[Database ${mutexId}] 关闭旧数据库连接...`);
-        console.log(`[Database ${mutexId}] Web：切换用户，直接置空旧连接`);
-        db = null;
-        currentDbUserId = null;
-        isInitialized = false;
-      } else {
       try {
         await db.closeAsync();
+        console.log(`[Database ${mutexId}] 旧连接已关闭`);
       } catch (e) {
         console.warn(`[Database ${mutexId}] 关闭旧连接失败:`, e);
       }
       db = null;
       currentDbUserId = null;
       isInitialized = false;
+      
+      if (isWeb) {
+        await new Promise(r => setTimeout(r, 100));
       }
     }
     
@@ -285,17 +295,9 @@ export const closeDatabase = async (): Promise<void> => {
   await withMutex(async () => {
     if (!db) return;
     
-    const isWeb = typeof window !== 'undefined';
-    if (isWeb) {
-      console.log('[Database] Web 环境：跳过关闭数据库，避免 OPFS 句柄冲突');
-      db = null;
-      currentDbUserId = null;
-      isInitialized = false;
-      return;
-    }
-    
     try {
       await db.closeAsync();
+      console.log('[Database] 数据库已关闭');
     } catch (e) {
       console.warn('[Database] 关闭失败:', e);
     }