feat(eink): 4.2" 400x300 build with the misc-fixed 9x15 font, wide sim

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/helpers/ui/EinkGfxDisplay.h

@@ -14,7 +14,8 @@ class Adafruit_GFX;
 // (GxEPDDisplay.cpp on a board, the sim's target.cpp): it pulls in the font
 // tables.
 
-// EINK_LARGE_FONT: a landscape panel writes in the 8x13 at its own resolution.
+// EINK_LARGE_FONT: a landscape panel writes in the 8x13 at its own resolution
+// (1), or the 9x15 (2, the 4.2" 400x300).
 // Without it a landscape panel doubles the 6x9 (every pixel 2x2) -- for small
 // dense panels where 8x13 would be too fine. A portrait panel always uses the
 // 6x9: its narrow width wants the smaller cell.

src/helpers/ui/EinkGfxDisplayImpl.h

@@ -4,7 +4,13 @@
 
 #include "EinkGfxDisplay.h"
 #include "MiscFixedRenderer.h"
-#include "MiscFixed8x13Font.h"
+#if EINK_LARGE_FONT == 2
+  #include "MiscFixed9x15Font.h"
+  #define EINK_LARGE_GFXFONT MiscFixed9x15
+#else
+  #include "MiscFixed8x13Font.h"
+  #define EINK_LARGE_GFXFONT MiscFixed8x13
+#endif
 
 EinkGfxDisplay::EinkGfxDisplay(int w, int h, Adafruit_GFX& gfx, uint16_t ink, uint16_t paper)
     : DisplayDriver(w, h), _gfx(gfx), _ink(ink), _paper(paper), _curr(ink), _font(&MiscFixed) {
@@ -13,7 +19,7 @@ EinkGfxDisplay::EinkGfxDisplay(int w, int h, Adafruit_GFX& gfx, uint16_t ink, ui
 
 void EinkGfxDisplay::updateLayout() {
   const bool landscape = width() >= height();
-  _font = (EINK_LARGE_FONT && landscape) ? &MiscFixed8x13 : &MiscFixed;
+  _font = (EINK_LARGE_FONT && landscape) ? &EINK_LARGE_GFXFONT : &MiscFixed;
   _px = (!EINK_LARGE_FONT && landscape) ? 2 : 1;
   _cell_w = miscFixedCellW(*_font);
   _cell_h = _font->yAdvance;