feat(expo-persistence): add official expo sqlite adapter

Add a dedicated expo-sqlite persistence package with real simulator/emulator smoke coverage so Expo apps can use the official SQLite runtime instead of the op-sqlite wrapper.

Made-with: Cursor

Author: samwillis

packages/db-expo-sqlite-persisted-collection/README.md

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+# @tanstack/db-expo-sqlite-persisted-collection
+
+Thin SQLite persistence for Expo apps using the official `expo-sqlite` adapter.
+
+## Public API
+
+- `createExpoSQLitePersistence(...)`
+- `persistedCollectionOptions(...)` (re-exported from core)
+
+## Quick start
+
+```ts
+import * as SQLite from 'expo-sqlite'
+import { createCollection } from '@tanstack/db'
+import {
+  createExpoSQLitePersistence,
+  persistedCollectionOptions,
+} from '@tanstack/db-expo-sqlite-persisted-collection'
+
+type Todo = {
+  id: string
+  title: string
+  completed: boolean
+}
+
+const database = await SQLite.openDatabaseAsync(`tanstack-db.sqlite`)
+
+// One shared persistence instance for the whole database.
+const persistence = createExpoSQLitePersistence({
+  database,
+})
+
+export const todosCollection = createCollection(
+  persistedCollectionOptions<Todo, string>({
+    id: `todos`,
+    getKey: (todo) => todo.id,
+    persistence,
+    schemaVersion: 1, // Per-collection schema version
+  }),
+)
+```
+
+## Notes
+
+- This package targets the official `expo-sqlite` async database API.
+- `createExpoSQLitePersistence` is shared across collections.
+- Mode defaults (`sync-present` vs `sync-absent`) are inferred from whether a
+  `sync` config is present in `persistedCollectionOptions`.
+- The React Native `op-sqlite` wrapper remains available in
+  `@tanstack/db-react-native-sqlite-persisted-collection`.
+- Expo web is not part of the emulator-backed E2E path in this package. Use the
+  browser SQLite package for browser-focused persistence coverage.
+
+## E2E
+
+- `pnpm --filter @tanstack/db-expo-sqlite-persisted-collection test:e2e`
+  runs the shared Node-backed conformance suite.
+- `pnpm --filter @tanstack/db-expo-sqlite-persisted-collection test:e2e:expo:ios`
+  runs the real Expo iOS Simulator path.
+- `pnpm --filter @tanstack/db-expo-sqlite-persisted-collection test:e2e:expo:android`
+  runs the real Expo Android Emulator path.

packages/db-expo-sqlite-persisted-collection/e2e/expo-emulator-smoke.e2e.test.ts

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+import { expect, it } from 'vitest'
+import { ensureExpoEmulatorRuntime } from '../tests/helpers/expo-emulator-runtime'
+
+const runtimePlatform = process.env.TANSTACK_DB_EXPO_RUNTIME_PLATFORM?.trim()
+const shouldRun =
+  runtimePlatform === `ios` || runtimePlatform === `android`
+
+it.runIf(shouldRun)(
+  `runs a persistence smoke test inside a real Expo runtime`,
+  async () => {
+    const runtime = await ensureExpoEmulatorRuntime(
+      runtimePlatform === `android` ? `android` : `ios`,
+    )
+    const smokeResult = await runtime.runPersistenceSmokeTest(
+      `expo-runtime-smoke.sqlite`,
+    )
+
+    expect(smokeResult.insertedTitle).toBe(`Persisted from Expo runtime`)
+    expect(smokeResult.reloadedCount).toBe(1)
+  },
+)

packages/db-expo-sqlite-persisted-collection/e2e/expo-persisted-collection.e2e.test.ts

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+import { it } from 'vitest'
+import { createExpoSQLitePersistence } from '../src'
+import { runMobilePersistedCollectionConformanceSuite } from './mobile-persisted-collection-conformance-suite'
+
+const runtimePlatform = process.env.TANSTACK_DB_EXPO_RUNTIME_PLATFORM?.trim()
+
+if (!runtimePlatform) {
+  runMobilePersistedCollectionConformanceSuite(
+    `expo persisted collection conformance`,
+    (database) => createExpoSQLitePersistence({ database }),
+  )
+} else {
+  it.skip(`runs the conformance suite in shimmed e2e mode only`, () => {})
+}