leaderboard: fit tasks iframe to content (kill blank space)

The Tasks browser iframe was a fixed 90vh, so a short detail card left a large
blank gap above the Refresh button. Mirror the gallery's approach: size the
iframe to the document height on load / resize / view switch (and via a
ResizeObserver for lazy render images), so it shrinks to the detail card and
grows for the summary grid.

Co-authored-by: Cursor <cursoragent@cursor.com>

tasks.py

@@ -503,10 +503,22 @@ let currentIdx = -1;
 const total = document.querySelectorAll('.fixture-card').length;
 let query = '', typeFilter = 'all';
 
+// Size the embedding iframe to the document height so a short detail card
+// doesn't leave a tall blank gap (the host iframe is otherwise a fixed
+// height). srcdoc iframes are same-origin, so frameElement is readable; a
+// no-op if it isn't (keeps the CSS fallback height).
+function fitFrame() {
+  try {
+    const fe = window.frameElement;
+    if (fe) fe.style.height = Math.ceil(document.documentElement.scrollHeight) + 'px';
+  } catch (e) { /* sandboxed -> keep fallback height */ }
+}
+
 function taskImgFail(img) {
   const view = img.closest('.view');
   if (view) { view.style.display = 'none'; return; }
   img.style.display = 'none';
+  fitFrame();
 }
 
 // Live grid filter: the segmented control filters by type, the search
@@ -534,6 +546,7 @@ function applyFilter() {
   if (empty) empty.style.display = shown ? 'none' : '';
   const note = document.getElementById('countNote');
   if (note) note.textContent = shown + ' of ' + total + ' shown';
+  fitFrame();
 }
 
 (function wireControls() {
@@ -557,6 +570,7 @@ function showSummary() {
   document.getElementById('summary-view').style.display = '';
   document.getElementById('detail-view').style.display = 'none';
   currentIdx = -1;
+  fitFrame();
 }
 
 function showDetail(idx) {
@@ -568,6 +582,7 @@ function showDetail(idx) {
   currentIdx = idx;
   updateNav();
   window.scrollTo(0, 0);
+  fitFrame();
 }
 
 function updateNav() {
@@ -607,4 +622,11 @@ function openHashTarget() {
 }
 openHashTarget();
 window.addEventListener('hashchange', openHashTarget);
+
+// Keep the iframe height matched to the content: on first paint, on resize,
+// and whenever layout changes (lazy render images loading, view switches).
+fitFrame();
+window.addEventListener('load', fitFrame);
+window.addEventListener('resize', fitFrame);
+if (window.ResizeObserver) new ResizeObserver(fitFrame).observe(document.body);
 """