M0 step 7: Settings, About, Storage, first-boot setup

- lib/apps_model (host-tested): SettingsMenu (rows, readable values,
  choices, validation messages) and SetupWizard (names, Region
  confirmation, timezone; saves only when finished)
- AppManager: modal Apps that Home/Back can't leave (setup wizard)
- SettingsApp: all settings plus Storage (usage, erase SD behind a
  dialog) and About (version, node id, battery, memory, uptime) pages,
  replacing the temporary Diagnostics App
- SetupApp: first-boot wizard, opened modally until SetupDone
- Node id and default names derived from the MAC like Meshtastic
- Widget demo is now hidden (About, then w)
- lib_ldf_mode = deep+ so libraries see each other's headers

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/apps/setup_app.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "app.h"
+#include "app_manager.h"
+#include "list_model.h"
+#include "setup_wizard.h"
+#include "ui/theme.h"
+
+namespace roro {
+
+// First-boot setup, run as a modal App until finished.
+class SetupApp : public App {
+   public:
+    SetupApp(Settings& settings, AppManager& apps);
+    bool onKey(const KeyEvent& e) override;
+    void draw(Canvas& c) override;
+
+   private:
+    AppManager& apps_;
+    SetupWizard wizard_;
+    ListModel choices_{4};
+};
+
+}  // namespace roro