Fix ESLint warnings and errors

- Remove unused imports in test files
- Fix unused variable warnings
- Fix React unescaped entity warning in settings page
- Remove unused error parameters in catch blocks

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/api/__tests__/streams.test.ts

@@ -1,4 +1,4 @@
-import { GET } from '../streams/route';
+// import { GET } from '../streams/route';
 
 // Mock the database module
 jest.mock('@/lib/database', () => ({