fix: Add site.webmanifest to resolve PWA 404 error

Author: GeneAI

website/public/site.webmanifest

@@ -0,0 +1,21 @@
+{
+  "name": "Empathy Framework",
+  "short_name": "Empathy",
+  "description": "Level 4 Anticipatory Intelligence for AI-human collaboration",
+  "start_url": "/",
+  "display": "standalone",
+  "theme_color": "#6366f1",
+  "background_color": "#ffffff",
+  "icons": [
+    {
+      "src": "/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png"
+    }
+  ]
+}