feat: implement sensor connection and health check endpoints

realtime/src/routes/sensors.js

@@ -0,0 +1,14 @@
+const router = require('express').Router();
+const db = require('../store/db');
+
+router.get('/sensors', async (req, res) => {
+    try {
+        const result = await db.query('SELECT id, name FROM sensors', [], 'sensors');
+        res.json(result.rows);
+    } catch (err) {
+        console.error('Error fetching sensors', err);
+        res.status(500).json({ error: 'internal server error' });
+    }
+});
+
+module.exports = router;