Calendar analog clock with ticks and numerals; tiles without background

Firmware 0.2.16: the analog clock uses index strokes with 12/3/6/9
numerals on large cards and shows a calendar block (weekday, big day,
short month) beside the dial on single tiles; wide cards keep the digital
time and date. New palette key 'none' hides only the card fill and
border: geometry, padding and the pressed flash stay identical. Skeleton
frames and the render self-test honour the transparency.

App 0.2.15: 'Geen' in the background palette with a dashed mockup tile,
min_firmware 0.2.16 for such layouts, demo layout with the bare calendar
clock (--wide for the double-width clock). README and AGENTS note that
every push is a release and bumps the add-on version.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

components/smart_display/tile_palette.h

@@ -16,4 +16,6 @@ inline uint32_t color(const std::string &name) {
   if(name=="gray")return 0xE5E7EB;
   return 0;  // Automatic/default, including unknown future palette names.
 }
+// "Geen": no card behind the tile contents. Older firmware treats it as automatic.
+inline bool transparent(const std::string &name) { return name=="none"; }
 }