feat(ui): compact on-screen keyboard toggle for external keyboards

Add Settings > Keyboard "Ext. KB" row (boards with a CardKB-capable I2C
bus only): switching it to Compact hides the letter grid and special-row
icons in favour of a one-line status (script/page, caps) plus a Fn-shortcut
reminder, since an external-keyboard typist never looks at the on-screen
grid. Accent/placeholder popups still render as before. Off by default.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

examples/companion_radio/DataStore.cpp

@@ -551,6 +551,12 @@ void DataStore::loadPrefsInt(const char *filename, NodePrefs& _prefs, double& no
   rd(&_prefs.gpio4_mode, sizeof(_prefs.gpio4_mode));
   if (_prefs.gpio4_mode > 3) _prefs.gpio4_mode = 0;
 
+  // → 0xC0DE0023: append the external-keyboard compact-display toggle at the
+  // tail. A pre-0x23 file has no byte here; clamp to 0 (full grid, unchanged
+  // behaviour for upgraders).
+  rd(&_prefs.keyboard_cardkb_compact, sizeof(_prefs.keyboard_cardkb_compact));
+  if (_prefs.keyboard_cardkb_compact > 1) _prefs.keyboard_cardkb_compact = 0;
+
   // Schema sentinel: bumped on layout changes. Mismatch means an older file
   // (or a different schema); rd() already zero-inits any fields not present,
   // so we just log it — next savePrefs writes the current sentinel.
@@ -762,6 +768,7 @@ void DataStore::savePrefs(const NodePrefs& _prefs, double node_lat, double node_
     file.write((uint8_t *)&_prefs.gpio2_mode, sizeof(_prefs.gpio2_mode));
     file.write((uint8_t *)&_prefs.gpio3_mode, sizeof(_prefs.gpio3_mode));
     file.write((uint8_t *)&_prefs.gpio4_mode, sizeof(_prefs.gpio4_mode));
+    file.write((uint8_t *)&_prefs.keyboard_cardkb_compact, sizeof(_prefs.keyboard_cardkb_compact));
 
     // Tail sentinel — must be last. See NodePrefs::SCHEMA_SENTINEL. Its write is
     // the one we check: once the flash fills, writes return 0, so a good

examples/companion_radio/NodePrefs.h

@@ -422,6 +422,17 @@ struct NodePrefs {  // persisted to file
   uint8_t  gpio3_mode;
   uint8_t  gpio4_mode;
 
+  // Settings > Keyboard's "Ext. KB" row (boards with a second I2C bus for an
+  // optional CardKB, see ENV_PIN_SDA/ENV_PIN_SCL, only). When on, the
+  // on-screen keyboard skips drawing its full letter grid + special-row icons
+  // -- an external-keyboard typist never looks at them -- and shows a compact
+  // one-line status (current script/page, caps) instead; the accent and
+  // placeholder popups still render on top exactly as before (see
+  // KeyboardWidget::render()). Manual toggle rather than auto-detected, so it
+  // stays put even if the module is briefly unplugged. Default 0 (full grid,
+  // unchanged behaviour) on upgrade.
+  uint8_t  keyboard_cardkb_compact;
+
   // Single source of truth for the live-share option tables (shared by the Map
   // UI labels and the auto-send engine in UITask).
   static const uint8_t LOC_SHARE_MOVE_COUNT = 4;
@@ -484,7 +495,7 @@ struct NodePrefs {  // persisted to file
   // adding/removing/reordering fields in DataStore::savePrefs/loadPrefsInt so
   // older saves are detected on load and skipped (zero-init defaults kept).
   // High 24 bits identify the file format; low byte is the schema revision.
-  static const uint32_t SCHEMA_SENTINEL = 0xC0DE0022;
+  static const uint32_t SCHEMA_SENTINEL = 0xC0DE0023;
 
   // Bit-index for each home page. Used by page_order (entries store bit+1) and
   // by home_pages_mask. Single source of truth — both HomeScreen::pageBit/bitToPage
@@ -581,7 +592,9 @@ struct NodePrefs {  // persisted to file
 //   3. clamp it on load (an upgrader's file lacks it → stray bytes)
 //   4. bump SCHEMA_SENTINEL's low byte
 // (Padding can also shift sizeof; a "false" trip just means re-check + rebump.)
-// keyboard_main_alphabet (added in the prior bump) landed in existing tail
+// keyboard_cardkb_compact (0xC0DE0023) also landed in existing tail padding --
+// confirmed via a real build -- leaving sizeof unchanged at 2720.
+// keyboard_main_alphabet (added in an earlier bump) landed in existing tail
 // padding -- confirmed via a real build's sizeof() -- so that bump left the
 // size unchanged. bot_actions_dm/ch/room and gpio1..4_mode (the last two
 // bumps, 7 more uint8_t total) added 8 bytes, not 7 -- one byte of tail

examples/companion_radio/ui-new/KeyboardWidget.h

@@ -526,6 +526,30 @@ struct KeyboardWidget {
       return 50;
     }
 
+    // Compact mode (Settings > Keyboard's "Ext. KB" row): an external-keyboard
+    // typist never looks at the letter grid or special-row icons, so skip
+    // drawing them and show a one-line status (current script/page, caps)
+    // instead. row/col/page keep updating exactly as before even while this
+    // is on (arrows and Fn+letter both still work; the accent popup below
+    // still anchors on `row`), so nothing breaks if physical buttons get used
+    // meanwhile -- it just won't be visible which cell is selected.
+    if (prefs && prefs->keyboard_cardkb_compact) {
+      const int hh = lh + 2;
+      display.setColor(DisplayDriver::LIGHT);
+      display.fillRect(0, chars_y, display.width(), hh);
+      display.setColor(DisplayDriver::DARK);
+      const char* script_name = pageIsSymbols(page) ? "Symbols"
+                               : (scriptAt(page) == NodePrefs::KB_ALPHABET_CYRILLIC) ? "Cyrillic"
+                               : (scriptAt(page) == NodePrefs::KB_ALPHABET_GREEK)    ? "Greek"
+                                                                                     : "Latin";
+      char status[32];
+      if (pageIsSymbols(page)) snprintf(status, sizeof(status), "%s%s", script_name, caps ? " CAPS" : "");
+      else snprintf(status, sizeof(status), "%s %s%s", script_name, isT9() ? "T9" : "ABC", caps ? " CAPS" : "");
+      display.drawTextCentered(display.width() / 2, chars_y + 1, status);
+      display.setColor(DisplayDriver::LIGHT);
+      display.drawTextCentered(display.width() / 2, chars_y + hh + 2, "Fn+Tab menu");
+      display.drawTextCentered(display.width() / 2, chars_y + hh + 2 + lh, "Fn+letter accent");
+    } else {
       // character grid
       if (isT9()) {
         for (int r = 0; r < rows; r++) {
@@ -602,6 +626,7 @@ struct KeyboardWidget {
         }
         display.setColor(DisplayDriver::LIGHT);
       }
+    }
 
     // Accent popup: floats over the still-visible grid (same idea as the
     // placeholder overlay just below), anchored on the held letter's own row

examples/companion_radio/ui-new/SettingsScreen.h

@@ -73,6 +73,9 @@ class SettingsScreen : public UIScreen {
     KEYBOARD_TYPE,
     KEYBOARD_MAIN_ALPHABET,
     KEYBOARD_ALPHABET,
+#if defined(ENV_PIN_SDA) && defined(ENV_PIN_SCL)
+    KEYBOARD_CARDKB_COMPACT,
+#endif
     // Contacts section
     SECTION_CONTACTS, DM_FILTER, CH_FILTER, ROOM_FILTER,
     // Messages section
@@ -574,6 +577,12 @@ class SettingsScreen : public UIScreen {
       display.print("Additional");
       display.setCursor(valCol(display), y);
       display.print(NodePrefs::keyboardAlphabetLabel(p ? p->keyboard_alt_alphabet : 0));
+#if defined(ENV_PIN_SDA) && defined(ENV_PIN_SCL)
+    } else if (item == KEYBOARD_CARDKB_COMPACT) {
+      display.print("Ext. KB");
+      display.setCursor(valCol(display), y);
+      display.print((p && p->keyboard_cardkb_compact) ? "Compact" : "Full");
+#endif
     } else if (item == BATT_DISPLAY) {
       display.print("BattDisp");
       display.setCursor(valCol(display), y);
@@ -945,6 +954,13 @@ public:
       _dirty = true;
       return true;
     }
+#if defined(ENV_PIN_SDA) && defined(ENV_PIN_SCL)
+    if (_selected == KEYBOARD_CARDKB_COMPACT && p && (left || right || enter)) {
+      p->keyboard_cardkb_compact ^= 1;
+      _dirty = true;
+      return true;
+    }
+#endif
     if (_selected == DM_RESEND && p) {
       int n = p->dm_resend_count;
       if (right || enter) n = (n + 1) % 6;          // 0..5, wraps

release-notes.md

@@ -7,6 +7,7 @@
 - **Bot Trigger fields accept multiple phrases.** Pack several trigger words into one Trigger field, comma-separated (`hi,hello there,yo`) — matching any one of them fires the reply, same as before for a single phrase.
 - **Remote Bot Actions gain `!gpio1`..`!gpio4`** (Wio Tracker L1 only — 4 otherwise-unused pins). Each pin is independently set to Off/Input/Output (GPIO1/GPIO2 also offer Analog) from a new **Tools › GPIO** screen; `!gpio1 on`/`!gpio1 off` drives an Output pin remotely, a bare `!gpio1` reports the current mode and reading (including a millivolt value in Analog mode). Gated by the same per-target Actions toggle as `!buzz`/`!gps`/`!advert`.
 - **Optional CardKB support (Wio Tracker L1, Grove I2C) — full keyboard-only navigation.** Plug an M5Stack CardKB into the Grove connector and it's auto-detected at boot — no setting to flip. Typing goes straight into the message/name field instead of navigating the on-screen keyboard grid; arrows and Esc work as expected everywhere else too (including inside the placeholder and accent popups). Enter acts like the physical centre button (advances the on-screen grid selection) rather than submitting, so **Fn+Enter** sends the message/confirms the field from anywhere, **Fn+`<letter>`** opens that letter's accent popup directly (no arrow-hunting needed — handy for Polish/Czech/etc. diacritics), and **Fn+Tab** opens the Hold-Enter equivalent (Shift-lock, clear field) for whatever's selected; plain **Tab** still opens the Hold-Enter context menu everywhere else (message reply/navigate, Bot/Admin/Repeater menus, …).
+- **Settings › Keyboard gets an "Ext. KB" row** (boards that support CardKB, above). Switching it to **Compact** hides the on-screen letter grid and special-row icons — a CardKB typist never looks at them — replacing them with a one-line status (current script/page, caps) plus a reminder of the Fn shortcuts; the accent and placeholder popups still show normally. Off (**Full**) by default.
 
 ### Fixes