fix: restore waveform HTML before writing error to statusbar

The pending spinner (first yield) replaces the whole wf_container HTML
including the statusbar span. On quota error, we were trying to write
to wf_statusbar_* after it had been wiped. Fix: restore preRegenWaveHtml
first, then getElementById finds the span and error message shows correctly.

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

app.py

@@ -2210,19 +2210,9 @@ _GLOBAL_JS = """
           if (hadError) {
             var toastMsg = typeof errMsg === 'string' ? errMsg : JSON.stringify(errMsg);
 
-            // Show error in the status bar (always in our DOM, no cross-origin issues)
-            var statusBar = document.getElementById('wf_statusbar_' + slot_id);
-            if (statusBar) {
-              statusBar.style.color = '#e05252';
-              statusBar.textContent = '⚠ ' + toastMsg;
-              // Reset after 15s so user can try again
-              setTimeout(function() {
-                statusBar.style.color = '#888';
-                statusBar.textContent = 'Click a segment to regenerate \u00a0|\u00a0 Playhead syncs to video';
-              }, 15000);
-            }
-
-            // Restore waveform HTML to pre-regen snapshot
+            // Restore waveform HTML FIRST — the pending spinner may have replaced
+            // the container (including the statusbar span), so we need the original
+            // HTML back before we can write the error message into it.
             if (preRegenWaveHtml !== null) {
               var waveEl = document.getElementById('slot_wave_' + slot_id);
               if (waveEl) waveEl.innerHTML = preRegenWaveHtml;
@@ -2237,7 +2227,20 @@ _GLOBAL_JS = """
               }
             }
 
-            if (lbl) lbl.textContent = 'Regen failed';
+            // Now write error into status bar (container is restored so element exists)
+            var statusBar = document.getElementById('wf_statusbar_' + slot_id);
+            if (statusBar) {
+              statusBar.style.color = '#e05252';
+              statusBar.textContent = '\u26a0 ' + toastMsg;
+              setTimeout(function() {
+                statusBar.style.color = '#888';
+                statusBar.textContent = 'Click a segment to regenerate \u00a0|\u00a0 Playhead syncs to video';
+              }, 15000);
+            }
+
+            // Also update the segment label below the waveform
+            var lbl2 = document.getElementById('wf_seglabel_' + slot_id);
+            if (lbl2) lbl2.textContent = 'Quota exceeded — try again later';
           } else {
             if (lbl) lbl.textContent = 'Done';