Refactor monolithic modules and harden booking, email, and auth infrastructure.

Split oversized frontend API client, email service, and admin/booking pages into focused modules while preserving import surfaces, and add Redis-backed queues, stale booking cleanup, stronger auth, and scale deployment configs.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/routes/emails.ts

@@ -163,9 +163,8 @@ emailsRouter.put('/templates/:id', requireAuth(['admin']), zValidator('json', up
   
   const updateData: any = { updatedAt: getNow() };
   
-  // Only allow updating certain fields for system templates
-  const systemProtectedFields = ['slug', 'isSystem'];
-  
+  // System templates cannot have their slug or isSystem flag changed; only the
+  // editable fields below are applied.
   const allowedFields = ['name', 'subject', 'subjectEs', 'bodyHtml', 'bodyHtmlEs', 'bodyText', 'bodyTextEs', 'description', 'variables', 'isActive'];
   if (!existing.isSystem) {
     allowedFields.push('slug');
@@ -486,7 +485,7 @@ emailsRouter.post('/test', requireAuth(['admin']), async (c) => {
 
 // Get email queue status
 emailsRouter.get('/queue/status', requireAuth(['admin']), async (c) => {
-  const status = getQueueStatus();
+  const status = await getQueueStatus();
   return c.json({ status });
 });