🔧 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/style.css

@@ -0,0 +1,5 @@
+/* Simple extra styles on top of Tailwind. */
+body {
+  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
+    "Segoe UI", sans-serif;
+}