Settings: its rows in five groups

Settings had grown to 21 rows in one list. It opens on five groups (This
device, Display, GNSS and radio, Network, System); Enter opens one, Back
returns to the groups, and Back from the groups leaves Settings.

SettingsMenu holds the groups and which one is open (host-tested: every
setting is in exactly one group). The guide, the how-tos, the README,
the scripts' messages and the firmware's own name the new paths, such as
"Settings > System > Firmware".

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

src/apps/debug_console_page.h

@@ -15,7 +15,7 @@
 
 namespace roro {
 
-// Settings → Debug Console (ADR 0010): the switch, where to connect, and the token, which is shown
+// Settings → System → Debug Console (ADR 0010): the switch, where to connect, and the token, which is shown
 // here and nowhere else. Switching on makes a token if there's none; a new one, or one typed by
 // hand, ends the connection of whoever holds the old one.
 class DebugConsolePage {

src/apps/firmware_page.h

@@ -18,7 +18,7 @@
 
 namespace roro {
 
-// Settings → Firmware: the running version and its Probation, where to push Firmware Updates, the
+// Settings → System → Firmware: the running version and its Probation, where to push Firmware Updates, the
 // project's releases on Gitea (the latest, and the ten before it), and the Update Files on the SD
 // card (in /updates) to install from.
 class FirmwarePage {

src/apps/gnss_app.cpp

@@ -76,7 +76,7 @@ void GnssApp::draw(Canvas& c) {
         c.drawString(held ? "GNSS is paused" : "GNSS is off", 4, area.y + 4);
         c.setFont(&fonts::body);
         c.setTextColor(theme::kMuted);
-        c.drawString(held ? "The LoRa radio is listening, and" : "Settings > GNSS turns it on.", 4, area.y + 22);
+        c.drawString(held ? "The LoRa radio is listening, and" : "On: Settings > GNSS and radio > GNSS", 4, area.y + 22);
         if (held) c.drawString("Settings pauses GNSS for it.", 4, area.y + 22 + theme::kLineHeight);
         return;
     }

src/apps/launcher_app.h

@@ -11,7 +11,7 @@
 namespace roro {
 
 // Home screen: the visible Apps as a grid of icons, with the selected one's name under it, or as
-// a list of names (Settings > Launcher). Select opens one. An App with something going on has a
+// a list of names (Settings > Display > Launcher). Select opens one. An App with something going on has a
 // dot on its tile (App::badge, issue #9).
 class LauncherApp : public App {
    public:

src/apps/settings_app.cpp

@@ -15,7 +15,9 @@ using Row = SettingsMenu::Row;
 
 void SettingsApp::onEnter() {
     page_ = Page::Menu;
+    menu_.close();
     list_.setCount(menu_.count());
+    list_.select(0);
 }
 
 void SettingsApp::warn(const std::string& text) {
@@ -56,7 +58,12 @@ bool SettingsApp::onMenuKey(const KeyEvent& e) {
             if (menu_.kind(i) == Kind::Toggle) menu_.toggle(i);
             return true;
         case Key::Select: break;
-        default: return false;  // Back leaves Settings
+        case Key::Back:
+            if (!menu_.close()) return false;  // from the groups, Back leaves Settings
+            list_.setCount(menu_.count());
+            list_.select(menu_.groupIndex());
+            return true;
+        default: return false;
     }
     editingRow_ = i;
     switch (menu_.kind(i)) {
@@ -72,6 +79,11 @@ bool SettingsApp::onMenuKey(const KeyEvent& e) {
             break;
         case Kind::Toggle: menu_.toggle(i); break;
         case Kind::Slider: break;
+        case Kind::Group:
+            menu_.open(i);
+            list_.setCount(menu_.count());
+            list_.select(0);
+            break;
         case Kind::Page:
             switch (menu_.row(i)) {
                 case Row::Wifi:
@@ -194,16 +206,27 @@ std::vector<std::string> SettingsApp::aboutLines() const {
 void SettingsApp::draw(Canvas& c) {
     const auto& area = theme::kContent;
     switch (page_) {
-        case Page::Menu:
+        case Page::Menu: {
+            // An open group has its name on a line of its own, over its rows.
+            theme::Rect rows = area;
+            if (menu_.inGroup()) {
+                c.setFont(&fonts::bold);
+                c.setTextDatum(top_left);
+                c.setTextColor(theme::kMuted);
+                c.drawString(menu_.title().c_str(), 4, area.y + 1);
+                rows.y += theme::kLineHeight;
+                rows.h -= theme::kLineHeight;
+            }
             widgets::list(
-                c, list_, area, [this](int i) { return menu_.label(i); },
+                c, list_, rows, [this](int i) { return menu_.label(i); },
                 [this](int i) {
                     auto kind = menu_.kind(i);
-                    if (kind == Kind::Page) return std::string(">");
+                    if (kind == Kind::Page || kind == Kind::Group) return std::string(">");
                     if (kind == Kind::Slider) return "< " + menu_.value(i) + " >";
                     return menu_.value(i);
                 });
             break;
+        }
         case Page::Text:
             c.setFont(&fonts::body);
             c.setTextColor(theme::kMuted);

src/apps/settings_app.h

@@ -35,7 +35,7 @@ struct SettingsAppDeps {
     VpnService& vpn;
 };
 
-// Settings: every user-facing setting, plus the Wi-Fi, Firmware, Debug Console and About pages.
+// Settings: every user-facing setting, in groups, plus the Wi-Fi, VPN, Firmware, Debug Console and About pages.
 class SettingsApp : public App {
    public:
     explicit SettingsApp(const SettingsAppDeps& deps)

src/apps/vpn_page.h

@@ -16,7 +16,7 @@
 
 namespace roro {
 
-// Settings > VPN (issue #8): the switch, "Start with Wi-Fi", importing a `.conf` from the card
+// Settings > Network > VPN (issue #8): the switch, "Start with Wi-Fi", importing a `.conf` from the card
 // and forgetting it, and what the tunnel is doing. No key is ever on this page.
 class VpnPage {
    public:

src/apps/wifi_settings_page.h

@@ -17,7 +17,7 @@
 
 namespace roro {
 
-// Settings → Wi-Fi: the On/Off switch, the connection and its details, DNS and NTP servers, and
+// Settings → Network → Wi-Fi: the On/Off switch, the connection and its details, DNS and NTP servers, and
 // the Saved Networks: adding one from a scan or by name (hidden), and each one's own page with its
 // IP setting, Automatic or Fixed (docs/milestones/S1.md, Q113). Owned by the Settings App.
 class WifiSettingsPage {