feat: play the Nth YouTube result in browseAndPlay via an index arg

agents/llm.md promises "play the Nth video from the top", but browseAndPlay
only ever clicked the first result. Add an optional 1-based index argument
(default 1, backward-compatible) threaded to the Node helper, which now clicks
the Nth a#video-title and clamps to the number of results returned so asking
beyond the list plays the last available video instead of failing.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

bot/scripts/stream-test/browse-search.mjs

@@ -2,10 +2,11 @@
 // 9222) so the action is visible on the Go-Live broadcast, and prints a JSON
 // result on stdout for the Python `browseAndSearch` tool to wrap.
 //
-//   node browse-search.mjs "<query>" [search|youtube]
+//   node browse-search.mjs "<query>" [search|youtube] [index]
 //
 // - search  : Google-search the query, return the top organic results.
-// - youtube : search YouTube and play the first result.
+// - youtube : search YouTube and play a result. `index` is the 1-based position
+//             from the top of the result list (default 1 = first result).
 //
 // Backend selection for `search`:
 //   1. The broadcast Chrome over CDP (visible on the Go-Live stream).
@@ -29,6 +30,9 @@ const UA =
   '(KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36';
 const query = process.argv[2] || '';
 const mode = (process.argv[3] || 'search').toLowerCase();
+// 1-based position of the YouTube result to play, counted from the top of the
+// list. Defaults to 1 (first result). Anything <1 or non-numeric falls back to 1.
+const playIndex = Math.max(1, parseInt(process.argv[4], 10) || 1);
 const out = (o) => { process.stdout.write(JSON.stringify(o)); };
 
 if (!query) { out({ ok: false, error: 'no query' }); process.exit(1); }
@@ -105,15 +109,21 @@ try {
   await page.bringToFront().catch(() => {});
 
   if (mode === 'youtube') {
-    // Type into YouTube's search box like a person, then play the first result.
+    // Type into YouTube's search box like a person, then play the requested
+    // result (the Nth from the top of the list; default the first).
     await typeSearch('https://www.youtube.com/?hl=ko', 'input#search, input[name="search_query"]', query);
     await page.waitForSelector('ytd-video-renderer a#video-title, a#video-title', { timeout: 20000 });
-    const first = page.locator('ytd-video-renderer a#video-title, a#video-title').first();
-    const title = (await first.getAttribute('title').catch(() => '')) || (await first.innerText().catch(() => ''));
-    await first.click();
+    const results = page.locator('ytd-video-renderer a#video-title, a#video-title');
+    // Clamp to what's actually on the page so "play the 5th" still plays the
+    // last available result rather than failing when fewer were returned.
+    const available = await results.count();
+    const targetIdx = Math.min(playIndex, Math.max(available, 1)) - 1;
+    const target = results.nth(targetIdx);
+    const title = (await target.getAttribute('title').catch(() => '')) || (await target.innerText().catch(() => ''));
+    await target.click();
     await page.waitForSelector('#movie_player', { timeout: 20000 });
     await page.evaluate(() => { const v = document.querySelector('video'); if (v && v.paused) v.play(); });
-    out({ ok: true, mode, title: (title || '').trim(), url: page.url() });
+    out({ ok: true, mode, index: targetIdx + 1, title: (title || '').trim(), url: page.url() });
   } else {
     // Type into Google's search box like a person, then read the results.
     await typeSearch('https://www.google.com/?hl=ko', 'textarea[name="q"], input[name="q"]', query);