feat: add competition heats system backend

- Add 3 new database tables: divisions, competition_types, event_user_heats
- Add seed data for 6 divisions (NEW, NOV, INT, ADV, ALL, CHA) and 2 competition types (J&J, STR)
- Add API endpoints for divisions and competition types
- Add heats management endpoints in events route (POST/GET/DELETE)
- Implement unique constraint: cannot have same role in same division+competition type
- Add participant verification before allowing heats management
- Support heat numbers 1-9 with optional Leader/Follower role

backend/src/routes/divisions.js

@@ -0,0 +1,31 @@
+const express = require('express');
+const { prisma } = require('../utils/db');
+
+const router = express.Router();
+
+// GET /api/divisions - List all divisions (public)
+router.get('/', async (req, res, next) => {
+  try {
+    const divisions = await prisma.division.findMany({
+      orderBy: {
+        displayOrder: 'asc',
+      },
+      select: {
+        id: true,
+        name: true,
+        abbreviation: true,
+        displayOrder: true,
+      },
+    });
+
+    res.json({
+      success: true,
+      count: divisions.length,
+      data: divisions,
+    });
+  } catch (error) {
+    next(error);
+  }
+});
+
+module.exports = router;