Interaction · Pointer: resize, turn, band selection, and gpui's own drag

Resizable sizes a box from its right and bottom edges and a grip at
its corner, within its least and greatest size; the grip is a Tab stop
whose arrows resize a step. Rotatable turns an svg to its angle inside
a ring whose knob a drag moves, Shift snapping to 15 degrees, with the
arrows turning it a notch. SelectionArea selects items with a band
drawn on empty space, a press, Command or Shift to add, and a cursor
the arrows walk with Space to add or drop; Escape clears and
Command-A takes all. The gallery shows gpui's own drag and drop, drag
preview, double press and wheel zoom, with pointers for Sortable,
LongPress and PanZoom; pinch stays blocked, gpui 0.2.2 forwards no
magnify event.

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

examples/gallery/pages/mod.rs

@@ -18,6 +18,7 @@ mod finance;
 mod forms;
 mod generative;
 mod git;
+mod interaction;
 mod layout;
 mod lists;
 mod mail;
@@ -89,6 +90,7 @@ pub const ALL: &[Page] = &[
     settings::PAGE,
     account::PAGE,
     onboarding::PAGE,
+    interaction::PAGE,
     theme::PAGE,
 ];