fix(security): harden security headers across API and Web apps

- API: set X-Frame-Options to DENY via frameguard, add Permissions-Policy header, widen CSP connect-src for Swagger CDN
- Web: add HSTS header (1yr, includeSubDomains, preload), add payment=(self) to Permissions-Policy, make localhost:3001 in CSP connect-src dev-only

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/main.ts

@@ -61,7 +61,7 @@ async function bootstrap() {
           scriptSrc: ["'self'", "'unsafe-inline'", 'https://cdn.jsdelivr.net'],
           styleSrc: ["'self'", "'unsafe-inline'", 'https://cdn.jsdelivr.net'],
           imgSrc: ["'self'", 'data:', 'https:', 'blob:'],
-          connectSrc: ["'self'"],
+          connectSrc: ["'self'", 'https://cdn.jsdelivr.net'],
           fontSrc: ["'self'", 'data:'],
           objectSrc: ["'none'"],
           frameSrc: ["'none'"],
@@ -72,11 +72,21 @@ async function bootstrap() {
       crossOriginEmbedderPolicy: true,
       crossOriginOpenerPolicy: true,
       crossOriginResourcePolicy: { policy: 'same-origin' },
+      frameguard: { action: 'deny' },
       hsts: { maxAge: 31536000, includeSubDomains: true, preload: true },
       referrerPolicy: { policy: 'strict-origin-when-cross-origin' },
     }),
   );
 
+  // ── Permissions-Policy Header ──
+  app.use((_req: unknown, res: { setHeader: (name: string, value: string) => void }, next: () => void) => {
+    res.setHeader(
+      'Permissions-Policy',
+      'camera=(), microphone=(), geolocation=(self), payment=(self)',
+    );
+    next();
+  });
+
   // ── Cookie Parser (required for CSRF double-submit pattern) ──
   app.use(cookieParser());