docs: tick the drawn chevron

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/IRIS_TODO.md

@@ -819,7 +819,11 @@ has the fuller account.
   nothing on screen says it was cut. Whichever end is cut has to be a
   choice when this lands: a path is identified by its tail, a command by
   its head.
-- [ ] **A drawn chevron.** *Still open, and now worse: the bundled fonts
+- [x] **A drawn chevron.** **Done 2026-09-08**: `iris::widget::mark(dir,
+  dp, colour)` rasterises an antialiased triangle into the ordinary
+  texture path and scales it into the box asked for, so no line/path
+  primitive was needed after all. `tool.rs` uses it for all three marks.
+  The original entry, for the record: *the bundled fonts
   were removed on 2026-09-07 in favour of the platform collection, so the
   mark is a codepoint the phone's own faces may not have -- Iris's
   2026-09-08 screenshot shows an empty box where it should be, and the