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

lib/core/src/app.h

@@ -50,6 +50,10 @@ class App {
     virtual bool retainsContent() const { return false; }
     virtual void contentLost() {}
 
+    // True while something goes on in the App that is worth a look, whether it is in front or
+    // not (unread messages, a recording running): the Launcher marks its tile (issue #9).
+    virtual bool badge() const { return false; }
+
     void requestRedraw() { redraw_ = true; }
 
     bool consumeRedraw() {

lib/core/src/app_keys.h

@@ -48,7 +48,7 @@ inline constexpr KeyHelp kText[] = {
 
 // launcher: The Launcher
 inline constexpr KeyHelp kLauncher[] = {
-    {"; .", "up, down"},
+    {"; . , /", "move"},
     {"Enter", "open the App"},
 };
 

lib/core/src/app_manager.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <cstdint>
+
 #include <string>
 #include <vector>
 
@@ -12,6 +14,7 @@ struct AppInfo {
     const char* title;
     bool hidden;  // not listed in the Launcher, but can still be opened
     App* app;
+    const uint8_t* icon = nullptr;  // the Launcher's picture of it (ui/icons.h); none: its first letter
 };
 
 // Owns which App is in the foreground and routes keys. Home always returns to the Launcher;