Harden auth, payments, and frontend against review findings.

Close exploitable gaps in booking/payment flows, enforce token versioning and account checks, gate sensitive payment data, and add middleware plus input validation across admin routes.

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

backend/src/routes/legal-pages.ts

@@ -162,6 +162,13 @@ legalPagesRouter.get('/', async (c) => {
 legalPagesRouter.get('/:slug', async (c) => {
   const { slug } = c.req.param();
   const locale = c.req.query('locale') || 'en';
+
+  // Reject anything that isn't a simple slug. The filesystem fallback below builds a
+  // path from this value, so an unconstrained slug (e.g. "../../etc/passwd") would
+  // allow path traversal / arbitrary file reads.
+  if (!/^[a-z0-9-]+$/.test(slug)) {
+    return c.json({ error: 'Legal page not found' }, 404);
+  }
   
   // First try to get from database
   const page = await dbGet<any>(
@@ -275,6 +282,17 @@ legalPagesRouter.put('/admin/:slug', requireAuth(['admin']), async (c) => {
   if (!enContent && !esContent) {
     return c.json({ error: 'At least one language content is required' }, 400);
   }
+
+  // Bound the sizes of admin-supplied content to avoid unbounded payloads.
+  const MAX_CONTENT_LEN = 200000; // ~200 KB of markdown per language
+  const MAX_TITLE_LEN = 255;
+  const tooLong = (v: any, max: number) => typeof v === 'string' && v.length > max;
+  if (tooLong(enContent, MAX_CONTENT_LEN) || tooLong(esContent, MAX_CONTENT_LEN)) {
+    return c.json({ error: `Content must be at most ${MAX_CONTENT_LEN} characters` }, 400);
+  }
+  if (tooLong(title, MAX_TITLE_LEN) || tooLong(titleEs, MAX_TITLE_LEN)) {
+    return c.json({ error: `Title must be at most ${MAX_TITLE_LEN} characters` }, 400);
+  }
   
   const existing = await dbGet(
     (db as any)