refactor: improve database reliability and clean up code

Enable WAL mode and set a busy timeout for SQLite to better handle
concurrent access and prevent 500 errors. Add error handling to
async calls in UI components and remove unused imports across several
files.

src/app/api/documents/blob/preview/ensure/route.ts

@@ -1,13 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server';
-import { and, eq, inArray } from 'drizzle-orm';
-import { db } from '@/db';
-import { documents } from '@/db/schema';
-import { requireAuthContext } from '@/lib/server/auth';
-import { isValidDocumentId } from '@/lib/server/documents-blobstore';
 import { presignDocumentPreviewGet } from '@/lib/server/document-previews-blobstore';
-import { ensureDocumentPreview, isPreviewableDocumentType } from '@/lib/server/document-previews';
-import { getOpenReaderTestNamespace, getUnclaimedUserIdForNamespace } from '@/lib/server/test-namespace';
-import { isS3Configured } from '@/lib/server/s3';
+import { ensureDocumentPreview } from '@/lib/server/document-previews';
 import { validatePreviewRequest } from '../utils';
 
 export const dynamic = 'force-dynamic';

src/app/api/documents/blob/preview/presign/route.ts

@@ -1,13 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server';
-import { and, eq, inArray } from 'drizzle-orm';
-import { db } from '@/db';
-import { documents } from '@/db/schema';
-import { requireAuthContext } from '@/lib/server/auth';
-import { isValidDocumentId } from '@/lib/server/documents-blobstore';
 import { presignDocumentPreviewGet } from '@/lib/server/document-previews-blobstore';
-import { ensureDocumentPreview, isPreviewableDocumentType } from '@/lib/server/document-previews';
-import { getOpenReaderTestNamespace, getUnclaimedUserIdForNamespace } from '@/lib/server/test-namespace';
-import { isS3Configured } from '@/lib/server/s3';
+import { ensureDocumentPreview } from '@/lib/server/document-previews';
 import { validatePreviewRequest } from '../utils';
 
 export const dynamic = 'force-dynamic';

src/components/PrivacyModal.tsx

@@ -134,7 +134,9 @@ export function PrivacyModal({ onAccept, authEnabled = false }: PrivacyModalProp
   }, []);
 
   useEffect(() => {
-    checkPrivacyAccepted();
+    checkPrivacyAccepted().catch((err) => {
+      console.error('Privacy acceptance check failed:', err);
+    });
   }, [checkPrivacyAccepted]);
 
   useEffect(() => {

src/components/SettingsModal.tsx

@@ -160,7 +160,9 @@ export function SettingsModal({ className = '' }: { className?: string }) {
   }, [setIsOpen]);
 
   useEffect(() => {
-    checkFirstVist();
+    checkFirstVist().catch((err) => {
+      console.error('First visit check failed:', err);
+    });
     setLocalApiKey(apiKey);
     setLocalBaseUrl(baseUrl);
     setLocalTTSProvider(ttsProvider);
@@ -170,7 +172,9 @@ export function SettingsModal({ className = '' }: { className?: string }) {
 
   useEffect(() => {
     const onPrivacyAccepted = () => {
-      checkFirstVist();
+      checkFirstVist().catch((err) => {
+        console.error('First visit check after privacy acceptance failed:', err);
+      });
     };
     window.addEventListener('openreader:privacyAccepted', onPrivacyAccepted);
     return () => {

src/components/documents/DexieMigrationModal.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { Fragment, useCallback, useEffect, useMemo, useRef, useState } from 'react';
+import { Fragment, useCallback, useEffect, useRef, useState } from 'react';
 import { Dialog, DialogPanel, DialogTitle, Transition, TransitionChild, Button } from '@headlessui/react';
 import { getAppConfig, getAllEpubDocuments, getAllHtmlDocuments, getAllPdfDocuments, updateAppConfig } from '@/lib/dexie';
 import { listDocuments, mimeTypeForDoc, uploadDocuments } from '@/lib/client-documents';

src/db/index.ts

@@ -74,6 +74,12 @@ function getDrizzleDB() {
       fs.mkdirSync(dir, { recursive: true });
     }
     const sqlite = new Database(dbPath);
+    // WAL mode allows concurrent readers + writer without blocking each other.
+    // busy_timeout retries on SQLITE_BUSY instead of failing immediately,
+    // which prevents 500 errors under concurrent API requests (e.g. multiple
+    // Playwright browser projects hitting the server simultaneously).
+    sqlite.pragma('journal_mode = WAL');
+    sqlite.pragma('busy_timeout = 5000');
     dbInstance = drizzleSqlite(sqlite, { schema: { ...schema, ...authSchemaSqlite } });
   }