feat(0.2.1): M3 前端 PowerSync 基础 (schema/connector/db) + 依赖; fix storage sslmode

src/lib/powersync/db.js

@@ -0,0 +1,37 @@
+// PowerSync 本地库单例 (0.2.1 离线编辑)
+// 页面用法: usePowerSyncQuery 等见 src/lib/powersync/react.jsx; 写入用 db.execute/writeTransaction
+import { PowerSyncDatabase } from '@powersync/web'
+import { AppSchema } from './schema.js'
+import { IBoardConnector } from './connector.js'
+
+let dbInstance = null
+
+export function getPowersyncDb() {
+  if (!dbInstance) {
+    dbInstance = new PowerSyncDatabase({
+      schema: AppSchema,
+      database: {
+        // 默认 IDBBatchAtomicVFS (IndexedDB), 兼容性最广; WebView2 (Chromium) 后续可切 OPFS 加速
+        dbFilename: 'iboard-powersync.db',
+      },
+    })
+  }
+  return dbInstance
+}
+
+/** 登录后调用: 建立同步连接 (幂等) */
+export async function connectPowersync() {
+  const db = getPowersyncDb()
+  db.connect(new IBoardConnector())
+  return db
+}
+
+/** 退出登录时调用: 断开同步并清空本地库 */
+export async function disconnectAndClearPowersync() {
+  if (!dbInstance) return
+  try {
+    await dbInstance.disconnectAndClear()
+  } catch {
+    /* ignore */
+  }
+}