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

test/test_settings/test_settings.cpp

@@ -4,29 +4,12 @@
 #include <map>
 #include <string>
 
+#include "../memory_store.h"
 #include "event_bus.h"
 #include "settings.h"
 
 using namespace roro;
 
-struct MemoryStore : KeyValueStore {
-    std::map<std::string, int32_t> ints;
-    std::map<std::string, std::string> strings;
-    bool getInt(const char* key, int32_t& out) override {
-        auto it = ints.find(key);
-        if (it == ints.end()) return false;
-        out = it->second;
-        return true;
-    }
-    bool getString(const char* key, std::string& out) override {
-        auto it = strings.find(key);
-        if (it == strings.end()) return false;
-        out = it->second;
-        return true;
-    }
-    void putInt(const char* key, int32_t v) override { ints[key] = v; }
-    void putString(const char* key, const std::string& v) override { strings[key] = v; }
-};
 
 void setUp() {}
 void tearDown() {}