Record #17, and queue the render state behind Rc<RefCell>

docs/IRIS_EXTRACTION_HANDOFF.md

@@ -12,6 +12,10 @@ in.
   `f192f75`. A widget sizes itself while drawing; `SizeCtx`, the `desired_*`
   methods and the size cache are gone, and `size_dependence(axis)` drives the
   retained path. `tabs`, `view` and `minimal` render byte-identical to `main`.
+- **#17** `split/17-headless-rig`, worktree `/home/bob/repos/iris-pr17`, head
+  `9d13f15`. The compositor script, `rig-input`'s `replay-touch` and the
+  `.touch` parser, so a rendering claim no longer has to be checked from
+  ai-app's checkout. Small, and disjoint from #16.
 
 Check for a review before starting anything, and read the newest
 `submitted_at` rather than the first result:
@@ -111,6 +115,8 @@ Still in the target, roughly in dependency order:
   slot ids and a bounded chain walk in WGSL, so moving a subtree writes one
   slot instead of every descendant's primitives. Agreed to come directly after
   #16.
+- **`UiRenderState` behind `Rc<RefCell<..>>`**, queued by the owner on
+  2026-09-13 as fundamental, and especially so for text. After the two below.
 - **Built-in alignment, and possibly size**, directly after the position
   chain. A child of a span is handed the full extent on the ortho axis, so
   `.width(rel(0.5))` inside a `Dir::DOWN` span changes what the child reports
@@ -133,10 +139,6 @@ Still in the target, roughly in dependency order:
   platform cancellation, mask-aware hit testing, event timestamps. The
   archive's own `consumes` is what #12 landed, so that part transplants;
   `tests/pointer_routing.rs` is the acceptance criterion.
-- **The headless rig.** `scripts/run-headless.sh`, `headless.conf` and
-  `rig-input` are still only in ai-app's iris submodule, so a rendering claim
-  in canonical Iris is still verified by hand from another checkout. Small, and
-  independent of everything above.
 - Retained span, scrolling and layout placement.
 - Retained paints, selection, overlays and shared UI runtime state.
 - Generic desktop/Android framework hosts and reusable example/APK tooling.