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

lib/apps_model/src/setup_wizard.h

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <string>
+
+#include "line_editor.h"
+#include "settings.h"
+
+namespace roro {
+
+// The first-boot setup flow: names, Region confirmation, timezone. Nothing is saved until the
+// last step, so an interrupted setup simply starts again at the next boot.
+class SetupWizard {
+   public:
+    enum class Step { Welcome, LongName, ShortName, Region, Timezone, Done };
+
+    SetupWizard(Settings& settings, std::string defaultLongName, std::string defaultShortName);
+
+    Step step() const { return step_; }
+    bool finished() const { return finished_; }
+
+    // Name steps edit text; Region and Timezone steps pick a choice.
+    LineEditor& editor() { return editor_; }
+    int choiceCount() const;
+    std::string choiceLabel(int i) const;
+    int selectedChoice() const;
+    void selectChoice(int i);
+
+    bool next();  // validates the step; false (with error()) if it can't advance
+    void back();
+    const std::string& error() const { return error_; }
+
+   private:
+    void enter(Step step);
+    void save();
+
+    Settings& settings_;
+    Step step_ = Step::Welcome;
+    bool finished_ = false;
+    std::string error_;
+    LineEditor editor_{39};
+    std::string longName_, shortName_;
+    int region_ = 0;
+    int timezone_ = 0;
+};
+
+}  // namespace roro