Fix monitor.js missing from Docker image and SQLITE_CANTOPEN errors

- Copy monitor.js into the standalone build stage (was missing entirely)
- Remove node-fetch require — Node 18 has global fetch built-in
- Switch from bind mount (./data) to named volume (dashboard-data) so
  Docker manages permissions correctly for the nextjs user

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

monitor.js

@@ -1,7 +1,6 @@
 const sqlite3 = require('sqlite3');
 const { open } = require('sqlite');
-const fetch = require('node-fetch'); // Native fetch in Node 18, but let's be safe or use global fetch
-// Node 18 has global fetch, so we don't need node-fetch if running with node 18
+// Node 18+ has global fetch built-in
 
 const SERVICES = [
     { name: 'Website', url: 'https://www.akkolli.net' },