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/unit/services/DatabaseService.test.ts

@@ -16,7 +16,7 @@ describe('DatabaseService', () => {
     jest.restoreAllMocks();
     try {
       databaseService.close();
-    } catch (e) {
+    } catch {
       // Ignore close errors in tests
     }
   });