refactor(admin): make Admin remote-only, move device settings to Settings

A device administering itself via the Admin tool read as awkward, so the
local mode is gone and its options relocated to Settings.

- AdminScreen is remote-only: drop the CHOOSER phase, _local_mode, the
  LocalField/LocalKind model and activateLocalField/commitLocalField.
  Phases collapse to LOGIN/COMMAND/REPLY, entered only via startFor().
- Tools > Admin opens straight to the Nodes picker (ACT_ADMIN ->
  pickAdminTarget()). Backing out of a command screen returns to that
  picker; the picker's Cancel returns to Tools. gotoAdminScreen() removed.
- Settings > System gains Name (keyboard-edited node_name) and Reboot
  (action row, placed last so it isn't the default cursor). Radio + TX
  power were already in Settings; Send advert is the home ADVERT page.

Docs: tools_screen.md Admin section rewritten remote-only; settings_screen.md
System table gains Name + Reboot.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/companion_radio/ui-new/SettingsScreen.h

@@ -64,9 +64,11 @@ class SettingsScreen : public UIScreen {
     TX_APC,
     // System section
     SECTION_SYSTEM,
+    DEVICE_NAME,
     TIMEZONE,
     LOW_BAT,
     UNITS,
+    REBOOT,
     // Keyboard section
     SECTION_KEYBOARD,
     KEYBOARD_TYPE,
@@ -554,6 +556,12 @@ class SettingsScreen : public UIScreen {
       display.print("Units");
       display.setCursor(valCol(display), y);
       display.print((p && p->units_imperial) ? "Imperial" : "Metric");
+    } else if (item == DEVICE_NAME) {
+      display.print("Name");
+      int vx = valCol(display);
+      display.drawTextEllipsized(vx, y, display.width() - vx - _reserve, the_mesh.getNodeName());
+    } else if (item == REBOOT) {
+      display.print("Reboot");   // action row: Enter reboots this device
     } else if (item == KEYBOARD_TYPE) {
       display.print("Type");
       display.setCursor(valCol(display), y);
@@ -632,6 +640,7 @@ class SettingsScreen : public UIScreen {
 
   // Keyboard state for editing message slots
   int            _edit_slot = -1;  // -1 = not editing, 0..9 = slot being edited
+  bool           _edit_name = false;  // editing DEVICE_NAME via the keyboard
   KeyboardWidget* _kb;
 
   // Radio preset picker — names are too long for the value column, so Enter on
@@ -654,6 +663,7 @@ public:
 
   void onShow() override {
     _dirty = false;
+    _edit_name = false;
     resetList();
     _editor.freq.active = false;
   }
@@ -661,7 +671,7 @@ public:
   int render(DisplayDriver& display) override {
     display.setTextSize(1);
 
-    if (_edit_slot >= 0 || _picker.saving) {
+    if (_edit_slot >= 0 || _edit_name || _picker.saving) {
       return _kb->render(display);
     }
 
@@ -708,6 +718,22 @@ public:
       return true;
     }
 
+    // Keyboard editing mode for the device name
+    if (_edit_name) {
+      auto res = _kb->handleInput(c);
+      if (res == KeyboardWidget::DONE) {
+        if (p) {
+          strncpy(p->node_name, _kb->buf, sizeof(p->node_name) - 1);
+          p->node_name[sizeof(p->node_name) - 1] = '\0';
+          _dirty = true;   // savePrefsIfDirty on exit; getNodeName()/self-advert read node_name live
+        }
+        _edit_name = false;
+      } else if (res == KeyboardWidget::CANCELLED) {
+        _edit_name = false;
+      }
+      return true;
+    }
+
     // Digit-by-digit Freq editor
     if (_editor.active()) {
       if (_editor.handleFreqInput(c) && p) { _task->applyRadioParams(); _dirty = true; }
@@ -886,6 +912,18 @@ public:
       _dirty = true;
       return true;
     }
+    if (_selected == DEVICE_NAME && p && enter) {
+      _edit_name = true;
+      _kb->begin(the_mesh.getNodeName(), (int)sizeof(p->node_name) - 1);
+      _kb->clearPlaceholders();   // a device name is literal, not a message
+      return true;
+    }
+    if (_selected == REBOOT && enter) {
+      _task->savePrefsIfDirty(_dirty);   // don't lose pending edits across the restart
+      _task->showAlert("Rebooting...", 800);
+      board.reboot();
+      return true;
+    }
     if (_selected == KEYBOARD_TYPE && p && (left || right || enter)) {
       p->keyboard_type ^= 1;
       _dirty = true;