fix(pwa): allow Safari to cache icons for home screen display

Safari iOS skips the apple-touch-icon entirely when the response has
Cache-Control: no-store. Exempt /icons/* and /manifest.webmanifest
from the no-store policy so Safari can retain them for Add to Home Screen.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: dorlugasigal

src/server/index.js

@@ -63,7 +63,10 @@ function createTermBeamServer(overrides = {}) {
     res.setHeader('X-Content-Type-Options', 'nosniff');
     res.setHeader('X-Frame-Options', 'DENY');
     res.setHeader('Referrer-Policy', 'no-referrer');
-    res.setHeader('Cache-Control', 'no-store');
+    // PWA assets (icons, manifest) must be cacheable for Safari iOS home screen icons.
+    // Safari skips apple-touch-icon entirely when Cache-Control: no-store is set.
+    const isPwaAsset = req.path.startsWith('/icons/') || req.path === '/manifest.webmanifest';
+    res.setHeader('Cache-Control', isPwaAsset ? 'public, max-age=86400' : 'no-store');
     res.setHeader(
       'Content-Security-Policy',
       "default-src 'self'; script-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; img-src 'self' data:; connect-src 'self' ws: wss: https://cdn.jsdelivr.net; font-src 'self' https://cdn.jsdelivr.net",

test/integration.test.js

@@ -349,6 +349,17 @@ describe('Integration', () => {
       assert.strictEqual(res.headers['referrer-policy'], 'no-referrer');
       assert.strictEqual(res.headers['cache-control'], 'no-store');
     });
+
+    it('PWA assets should have cacheable headers for Safari iOS', async () => {
+      if (!inst) inst = await startServer();
+      const res = await httpRequest({
+        hostname: '127.0.0.1',
+        port: inst.port,
+        path: '/manifest.webmanifest',
+        method: 'GET',
+      });
+      assert.strictEqual(res.headers['cache-control'], 'public, max-age=86400');
+    });
   });
 
   describe('Rate limiting on login', () => {