Add API documentation and underground station importer

- Introduced a new HTML documentation page for the oradio API, including a JavaScript file to handle dynamic content and API requests.
- Added a CSS file for styling the documentation page.
- Implemented an underground station importer script that fetches data from Radio-Browser and writes it to a JSON file.
- Created a stats module to compute and manage vote and play statistics for radio stations.
- Added a polyfill for modulepreload to ensure compatibility with older browsers.

server/streams/checker.js

@@ -5,21 +5,21 @@ import { probeStream } from './probe.js';
 const probe = probeStream;
 
 export async function runHealthCheck() {
-  const db = getDb();
-  const streams = db.prepare('SELECT id, url FROM streams').all();
-  const update = db.prepare(
-    "UPDATE streams SET last_status = ?, last_checked_at = datetime('now') WHERE id = ?"
-  );
-  for (const s of streams) {
-    const status = await probe(s.url);
-    update.run(status, s.id);
-  }
-  return streams.length;
+    const db = getDb();
+    const streams = db.prepare('SELECT id, url FROM streams').all();
+    const update = db.prepare(
+        "UPDATE streams SET last_status = ?, last_checked_at = datetime('now') WHERE id = ?"
+    );
+    for (const s of streams) {
+        const status = await probe(s.url);
+        update.run(status, s.id);
+    }
+    return streams.length;
 }
 
 export function scheduleHealthCheck(expr) {
-  if (!expr) return null;
-  return cron.schedule(expr, () => {
-    runHealthCheck().catch((err) => console.error('[health]', err));
-  });
+    if (!expr) return null;
+    return cron.schedule(expr, () => {
+        runHealthCheck().catch((err) => console.error('[health]', err));
+    });
 }