Messaging · Stickers and GIFs: a sticker picker and a GIF picker

StickerPicker shows stickers a pack at a time, chosen above with a
segmented control; a search spans every pack and keeps the stickers
whose names hold it. Arrows move, Enter or a press picks. It reuses the
glyph grid, now forms::picks, which takes its columns and cell size and
titles from the host, so emoji, icons and stickers share one searchable
grid; forms::glyphs keeps the emoji and icon pickers.

GifPicker packs host GIFs in two columns, each moving, under a search
it owns; the host hears the trimmed words only when they change, and
categories fill the search while it is empty. Waiting, it shows tiles
in GIF shapes; finding nothing, it says so. Each GIF is a Tab stop that
a press, Enter or Space picks.

The share toggle now shows its state, as the microphone and camera do.
The gallery ships line-drawn stickers and small GIFs made from its own
pictures.

tasks/ch21-30.md

@@ -357,8 +357,8 @@
 
 ## T28e Messaging · Stickers and GIFs
 
-- [ ] StickerPicker
-- [ ] GifPicker — host images
+- [x] StickerPicker
+- [x] GifPicker — host images
 
 ## T29 Mail — `src/mail`