fix: adaptive layout for e-ink landscape across all remaining screens

- GxEPDDisplay: sz2 uses 4× scale on landscape (clock 32px vs body 16px)
- UITask: clock date_y and splash date_y computed from lh2 after setTextSize(2)
- UITask: battery/mute/BT/advert indicators scale with lh; muted uses text 'M'
- UITask: hibernate hint split into two lines to prevent wrapping
- ToolsScreen: full refactor — headerH, listStart, lineStep, getCharWidth
- KeyboardWidget: all cell sizes computed from display metrics (cell_w, cell_h, spec_w)
- RingtoneEditorScreen: cell_w = charWidth×2+6 (was hardcoded 18)
- SettingsScreen: BRIGHTNESS hidden on e-ink; renderBar boxes scale with lh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/helpers/ui/GxEPDDisplay.cpp

@@ -92,7 +92,7 @@ void GxEPDDisplay::setTextSize(int sz) {
       break;
     case 2:
       display.setFont(NULL);
-      display.setTextSize(2);
+      display.setTextSize((width() >= height()) ? 4 : 2);
       break;
     default:
       display.setFont(_use_lemon ? &Lemon : NULL);

src/helpers/ui/GxEPDDisplay.h

@@ -73,13 +73,13 @@ public:
   int getCharWidth() const override {
     int sc = (width() >= height()) ? 2 : 1;
     if (_text_sz == 3) return 17;
-    if (_text_sz == 2) return 12;
+    if (_text_sz == 2) return 12 * sc;
     return (_use_lemon ? 5 : 6) * sc;
   }
   int getLineHeight() const override {
     int sc = (width() >= height()) ? 2 : 1;
     if (_text_sz == 3) return 28;
-    if (_text_sz == 2) return 16;
+    if (_text_sz == 2) return 16 * sc;
     return (_use_lemon ? 10 : 8) * sc;
   }
   void setLemonFont(bool enabled) override { _use_lemon = enabled; }