fix: PWA manifest was never linked, icons 404'd; add install prompt (v0.64.0)

layout.tsx pointed <link rel="manifest"> at /manifest.json, but the
actual generated route (app/manifest.ts) serves at
/manifest.webmanifest -- the manifest was silently never picked up.
Its icons also referenced icon-192.png/icon-512.png, which don't
exist (only the .svg versions do). Both together meant Chrome/Android
install eligibility was broken with no visible error.

Also adds apple-mobile-web-app meta tags + viewport-fit=cover for
iOS home-screen installs, and a dismissible install banner driven by
the standard beforeinstallprompt event (Chromium-only by spec).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/lib/changelog.ts

@@ -1,5 +1,5 @@
 // Mirrors CHANGELOG.md at the repo root — update both together.
-export const APP_VERSION = "0.63.0";
+export const APP_VERSION = "0.64.0";
 
 export type ChangelogEntry = {
   version: string;
@@ -11,6 +11,17 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.64.0",
+    date: "2026-07-21 00:30",
+    fixed: [
+      "The web app manifest was never actually linked into the page (pointed at /manifest.json, but the real route is /manifest.webmanifest) and its icons referenced PNGs that don't exist in the repo — both silently broke install eligibility on Chrome/Android. Manifest now links correctly and icons point at the existing SVGs.",
+    ],
+    added: [
+      "Added apple-mobile-web-app meta tags and a viewport-fit=cover safe-area setting for iOS home-screen installs.",
+      "Added an install-app banner (Chrome/Edge/Android only, via the standard beforeinstallprompt event) so the PWA install prompt is a first-class, dismissible UI element instead of relying on the browser's own icon.",
+    ],
+  },
   {
     version: "0.63.0",
     date: "2026-07-21 00:15",