Reorganize frontend into public/ with pages/ and js/ subdirectories

- public/index.html — landing page at root
- public/pages/ — all feature pages (regulations, loadboard, etc.)
- public/js/ — api.js, nav.js, mock data files
- All links updated to absolute paths (/pages/, /js/)
- Express static path updated to serve from public/
- Seed script path updated for new mock data location
- README updated with new project structure and setup guide
- Added .env.example template

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

server/src/seeds/seed.js

@@ -11,7 +11,7 @@ const prisma = require('../config/db');
 
 // Load the mock data files by evaluating them in a controlled context
 function loadMockData(filename) {
-  const filepath = path.join(__dirname, '..', '..', '..', filename);
+  const filepath = path.join(__dirname, '..', '..', '..', 'public', 'js', filename);
   const code = fs.readFileSync(filepath, 'utf-8');
   const context = {};
   // Execute the JS to populate the const variables