chore: restructure project into backend and frontend folders

- Move all frontend code to frontend/ directory
- Add backend/ with Go project structure (cmd, internal, pkg)
- Add docker-compose.yml for orchestration

frontend/public/manifest.json

@@ -0,0 +1,21 @@
+{
+  "name": "Delivery Tracker",
+  "short_name": "Deliveries",
+  "description": "Система контроля доставок мебели",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#fbf8fb",
+  "theme_color": "#1B263B",
+  "icons": [
+    {
+      "src": "/icon-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/icon-512x512.png",
+      "sizes": "512x512",
+      "type": "image/png"
+    }
+  ]
+}