Add manifest, robots.txt, sitemap.xml, and thumbnail image for improved SEO and site structure

public/manifest.json

@@ -0,0 +1,19 @@
+{
+  "name": "Untrace - EXIF Metadata & AI Content Credential Remover",
+  "short_name": "Untrace",
+  "description": "Free online tool to remove EXIF metadata, GPS location data, AI generation tags, and content credentials from images",
+  "start_url": "/untrace/",
+  "display": "standalone",
+  "background_color": "#ffffff",
+  "theme_color": "#3b82f6",
+  "icons": [
+    {
+      "src": "vite.svg",
+      "sizes": "any",
+      "type": "image/svg+xml"
+    }
+  ],
+  "categories": ["productivity", "utilities", "photo"],
+  "lang": "en",
+  "orientation": "any"
+}