fix: landscape e-ink layout corrections — clock overlap, keyboard overflow, bar sizing, nearby detail

- GxEPDDisplay: fontAscender only applies to sz=1 with Lemon; sz=2 (NULL font)
  was incorrectly getting a 16px cursor offset, causing clock text to render
  16px lower than expected and overlap the date line
- KeyboardWidget: compute cell_h from available screen height instead of lh+1;
  tighten sep_y to lh so the grid fits within 122px even with Lemon font (lh=20)
- SettingsScreen renderBar: constrain box size to available width so the 5th
  buzzer-volume square doesn't overflow past the right edge with Lemon font
- NearbyScreen discover detail: manually truncate b64 public key by charWidth
  to guarantee one-line rendering; use dynamic step = (height-hdr)/5 so
  Status line doesn't fall off the bottom of the screen
- NearbyScreen contacts detail: merge dist+az into one line and use dynamic
  step to fit 5 lines within the display; removes the off-screen Seen: row
- AutoAdvertScreen: replace lineStep() gap before hints with 4px fixed gap
  so both hint lines fit within the display with large fonts

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

src/helpers/ui/GxEPDDisplay.cpp

@@ -17,9 +17,9 @@
 // coordinates (same convention as the OLED driver). Add the font ascender so
 // the two conventions match.
 static int fontAscender(int sz, bool use_lemon, int scale) {
-  if (sz == 3) return 26;              // FreeSans18pt7b: proportional, baseline origin
-  if (use_lemon) return 8 * scale;    // Lemon GFX font: baseline origin, ascender 8px×scale
-  return 0;                           // GFX built-in font: cursor is top-left of cell
+  if (sz == 3) return 26;                       // FreeSans18pt7b: proportional, baseline origin
+  if (sz == 1 && use_lemon) return 8 * scale;   // Lemon GFX font: baseline origin, ascender 8px×scale
+  return 0;                                     // GFX built-in font: cursor is top-left of cell
 }
 
 bool GxEPDDisplay::begin() {