Launcher: a grid of icons, with badges; the list stays as a Setting

The Launcher shows the Apps as a 4 x 3 grid of 32 x 32 icons, the
selected one's name under it (issue #9). The icons are the website's
own, doubled, and two drawn the same way for SSH and the Shell; they
are PNGs in assets/icons, turned into arrays by scripts/make_icons.py,
which CI checks. The selected tile is the website's: dark blue on cyan,
with notched corners.

- GridModel (lib/ui, host-tested) holds the selection and the scrolling.
- App::badge(): a dot on the tile for unread IRC messages, a Track
  recording, a Capture running, an SSH session open.
- Settings > Launcher: Grid or List.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0162FokPdvY2KsS4NBfwyWPk

.gitea/workflows/ci.yml

@@ -83,6 +83,9 @@ jobs:
           git checkout -q --detach "${{ github.sha }}"
           git describe --tags --always
 
+      - name: The icons are what their pictures give
+        run: python3 scripts/make_icons.py --check
+
       - name: Host tests, and their coverage of lib/
         if: github.event_name != 'workflow_dispatch'
         run: |