feat(branding): add PWA manifest and PNG logo assets

apps/web/index.html

@@ -7,6 +7,7 @@
     <meta name="description" content="Open-source, self-hosted image processing platform" />
     <meta name="theme-color" content="#3b82f6" />
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+    <link rel="manifest" href="/manifest.json" />
     <meta property="og:title" content="Stirling Image" />
     <meta property="og:description" content="Open-source, self-hosted image processing platform" />
     <meta property="og:type" content="website" />

apps/web/public/manifest.json

@@ -0,0 +1,11 @@
+{
+  "name": "Stirling Image",
+  "short_name": "Stirling Image",
+  "icons": [
+    { "src": "/logo-192.png", "sizes": "192x192", "type": "image/png" },
+    { "src": "/logo-512.png", "sizes": "512x512", "type": "image/png" }
+  ],
+  "theme_color": "#3b82f6",
+  "background_color": "#ffffff",
+  "display": "standalone"
+}