Clean up unused imports and variables to improve code quality

- Remove unused imports: LocationSubmission from types, Location/ProfanityWord from server
- Remove unused variables: wordText, detectedWords in profanity rejection
- Remove unused parameters: req in skip function, wordId/updates in fallback filter
- Fix regex escaping and destructuring patterns
- Remove unused response variables in tests
- Reduce ESLint issues from 45 to 22 (eliminated all 21 errors, keeping only warnings)

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

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

tests/integration/routes/public.test.ts

@@ -302,7 +302,7 @@ describe('Public API Routes', () => {
     });
 
     it('should handle malformed JSON', async () => {
-      const response = await request(app)
+      await request(app)
         .post('/api/locations')
         .set('Content-Type', 'application/json')
         .send('{"address": "Test Location"') // Missing closing brace