feat: weighted grid layout, pane list bar, sorted tabs, and idle sound delay

- Replace 70/30 rearranging split with weighted grid: focused pane's
  column/row get 70%, others shrink in place (no spatial reordering)
- Add clickable pane list row below tab bar in both grid and picker modes
- Sort grid tabs numerically by tab number
- Click on focused pane no longer unfocuses it
- Delay idle notification sound by 10s to filter false intermediate alerts
- Bump chrome top from 3 to 4 rows (tab bar, pane list, header, content)

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

src/index.ts

@@ -87,6 +87,12 @@ async function main() {
     flexShrink: 0,
   })
 
+  app.paneListText = new TextRenderable(app.renderer, {
+    width: "100%",
+    height: 1,
+    flexShrink: 0,
+  })
+
   app.headerText = new TextRenderable(app.renderer, {
     width: "100%",
     height: 1,
@@ -155,6 +161,7 @@ async function main() {
   })
 
   app.mainBox.add(app.tabBarText)
+  app.mainBox.add(app.paneListText)
   app.mainBox.add(app.headerText)
   app.mainBox.add(app.colHeaderText)
   app.mainBox.add(app.listBox)