feat: isolate profanity filter with separate database

- Create dedicated ProfanityFilter class with isolated SQLite database
- Separate profanity.db from main application database to prevent SQLITE_MISUSE errors
- Add comprehensive custom word management (CRUD operations)
- Implement advanced profanity detection with leetspeak and pattern matching
- Add admin UI for managing custom profanity words
- Add extensive test suites for both profanity filter and API routes
- Update server.js to use isolated profanity filter
- Add proper database initialization and cleanup methods
- Support in-memory databases for testing

Breaking changes:
- Profanity filter now uses separate database file
- Updated admin API endpoints for profanity management
- Enhanced profanity detection capabilities

public/app-mapbox.js

@@ -453,7 +453,14 @@ document.addEventListener('DOMContentLoaded', async () => {
                     }),
                 });
             })
-            .then(res => res.json())
+            .then(res => {
+                if (!res.ok) {
+                    return res.json().then(errorData => {
+                        throw { status: res.status, data: errorData };
+                    });
+                }
+                return res.json();
+            })
             .then(location => {
                 refreshLocations();
                 messageDiv.textContent = 'Location reported successfully!';
@@ -462,17 +469,34 @@ document.addEventListener('DOMContentLoaded', async () => {
             })
             .catch(err => {
                 console.error('Error reporting location:', err);
-                messageDiv.textContent = 'Error reporting location.';
-                messageDiv.className = 'message error';
+                
+                // Handle specific profanity rejection
+                if (err.status === 400 && err.data && err.data.error === 'Submission rejected') {
+                    messageDiv.textContent = err.data.message;
+                    messageDiv.className = 'message error profanity-rejection';
+                    
+                    // Clear the description field to encourage rewriting
+                    document.getElementById('description').value = '';
+                    document.getElementById('description').focus();
+                } else if (err.data && err.data.error) {
+                    messageDiv.textContent = err.data.error;
+                    messageDiv.className = 'message error';
+                } else {
+                    messageDiv.textContent = 'Error reporting location. Please try again.';
+                    messageDiv.className = 'message error';
+                }
             })
             .finally(() => {
                 submitBtn.disabled = false;
                 submitText.style.display = 'inline';
                 submitLoading.style.display = 'none';
                 messageDiv.style.display = 'block';
+                
+                // Longer timeout for profanity rejection messages
+                const timeout = messageDiv.className.includes('profanity-rejection') ? 15000 : 3000;
                 setTimeout(() => {
                     messageDiv.style.display = 'none';
-                }, 3000);
+                }, timeout);
             });
     });