Add btop-style agent activity sidebar example

.github/workflows/ci-guards.yml

@@ -195,6 +195,10 @@ jobs:
         if: ${{ matrix.group == 'preflight' }}
         run: python3 tests/test_write_sidebar_extension_point.py
 
+      - name: Test btop agent sidebar example bounds
+        if: ${{ matrix.group == 'preflight' }}
+        run: python3 tests/test_btop_agents_sidebar.py
+
       - name: Validate settings rows advertise supported cmux.json paths
         if: ${{ matrix.group == 'preflight' }}
         run: python3 tests/test_settings_configuration_review_paths.py

Examples/CustomSidebars/README.md

@@ -31,5 +31,13 @@ cmux sidebar validate finder
   signals.
 - `finder.swift`: a macOS Finder-style workspace browser with a source list,
   selected workspace inspector, and tab list.
+- `btop-agents.js`: agent activity in the spirit of btop. Each workspace shows
+  a braille sparkline of how busy its agents were over the last six minutes,
+  a state glyph (spinner while working, amber diamond when waiting for input),
+  a tiny progress meter, unread count and PR number. The header graphs busy
+  workspaces over twelve minutes. Click a row to select it, drag to reorder,
+  and use BUSY to hide quiet workspaces. Install with
+  `cp Examples/CustomSidebars/btop-agents.js ~/.config/cmux/sidebars/` and
+  `cmux sidebar select btop-agents`.
 
 See `docs/custom-sidebars.md` for the full authoring contract.