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.

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

src/theme/messaging.rs

@@ -9,6 +9,8 @@ pub struct MessagingSizes {
     pub tiles: Rems,
     /// A call's tile at its narrowest, before a grid drops a column.
     pub tile: Rems,
+    /// A sticker's cell in a picker, square.
+    pub sticker: Rems,
 }
 
 impl Theme {
@@ -16,6 +18,7 @@ impl Theme {
         MessagingSizes {
             tiles: px_to_rems(200.0),
             tile: px_to_rems(160.0),
+            sticker: px_to_rems(64.0),
         }
     }
 }