Record PR 19 performance sweep and request invalidation fix

docs/HANDOFF.md

@@ -4,9 +4,35 @@ Where the work in flight stands. The settled layout design, the vocabulary
 and the measurement method are in `docs/LAYOUT.md`; what the review of #19
 found is in `docs/LAYOUT_LOG.md`.
 
+## Performance sweep is submitted on PR #19
+
+`layout/one-ask` is at `0e838e9` in `/home/bob/repos/iris-deferred`. The fix
+keeps dependencies only for size requests the allocator uses, and borrows
+`Widgets::size_rules` rather than cloning both axes at every lookup. Used
+hints retain their reader dependency; adding a cap after layout is checked for
+both hinted and measured shares. Ordinary text measurement still tracks its
+own dependencies. The app's Iris pin is untouched.
+
+Repeated release instruction counts reproduce the reported +5.9% resize cost
+and find a larger defect: an unchanged paragraph repaint invalidated its span,
+turning 0.376B instructions into 3.010B in a 40-paragraph, 2,000-frame fixture.
+The fix is 0.370B. Text resize is now +0.99% against `de1eb7e`, the width sweep
++1.23%, and edits/scroll are within 0.3%. `docs/LAYOUT_LOG.md` has the full
+performance sweep, including deep-tree regressions, RSS, upstream-base
+comparison, and GPU timestamp measurements. This is not a universal speedup.
+
+Passed: format, workspace Clippy with and without diagnostics, all 197 ordinary
+and 201 diagnostic workspace tests, zero steady allocation fixtures, 400
+depth-5 / 1,000 depth-6 / 2,000 depth-4 trees, 400 depth-5 expression trees,
+400 relative-bound trees, GPU recording and move-chain rigs, and identical
+cold geometry for all 34,986 bounded boxes against `8780b40`. Code and comments
+were reviewed separately; the final test/comment refinements passed their
+focused checks. Artifacts are under `/tmp/pr19-perf/`.
+
 ## Deferred comparisons are submitted on PR #19
 
-The `layout/one-ask` tip is `8780b40`, in `/home/bob/repos/iris-deferred`.
+The deferred-comparison implementation landed at `8780b40`, before the
+performance correction above.
 `/home/bob/repos/iris` remains on `layout/bounds`; that branch's `de1eb7e` was
 fast-forwarded into #19 before this work. The app's Iris pin is untouched.