🔧 chore(repo): restructure project file hierarchy

- move project files out of fleetledger directory to root
- update .gitignore to reflect new .env path

📝 docs(README): add detailed project description

- provide an overview of FleetLedger's features and usage
- include setup instructions and security notes

app/static/manifest.webmanifest

@@ -0,0 +1,20 @@
+{
+  "name": "FleetLedger",
+  "short_name": "FleetLedger",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#020617",
+  "theme_color": "#020617",
+  "icons": [
+    {
+      "src": "/static/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/static/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png"
+    }
+  ]
+}