docs/REVIEW-2026-09-06.md: fix all ten review findings; RUST.md/IRIS_TODO.md: DragGesture merge checks

Finding 1 (the real crash): Selection::clear() drops rows and anchor,
called from TranscriptScreen::apply's Rebuild arm right before
List::clear() -- push_row re-registers survivors as it rebuilds each row.
Fixes a WeakWidget outliving the row group_tool_runs regrouped away,
which panicked the next long-press anywhere. New apply_tests test builds
a real TranscriptScreen, forces the regroup, and confirms no panic.

Findings 2-5: debug_assert!s on List::place's slot, List::fling and
FlingCalculator's velocity finiteness, VelocityTracker::add_sample's
chronological order, and FrameReport::mark_phase's non-decreasing
start_index. Finding 7: bench_client.rs's battery_line guard restructured
so the empty check can't be separated from its unwraps by a future edit.
Findings 9/10: new List tests pinning tick_fling's per-tick deceleration
and replace_back's evicted-key cleanup with a different key than the
existing tests use. IRIS.md's replace_back/clear/apply entry gained the
side-table-clearing note the Docs finding asked for.

Also records this pass's DragGesture-merge verification in RUST.md (tap
stays vs swipe doesn't, a real fling keeps moving after release, keyboard
cycles confirmed via on_insets_changed) and annotates the two IRIS_TODO.md
phone-report items it targets.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/IRIS_TODO.md

@@ -203,17 +203,40 @@ agent ticks it here with the evidence.
   before the first `on_insets_changed`. Reproduce with the phone's
   screen size and density on the emulator before guessing.
 - [ ] **"Swiping still gets caught by the grey bar but keeps working
-  after I go past it."** A pan that starts on the composer is held by
-  the composer until the finger leaves its region, then the list takes
-  over. The tap-vs-swipe fix in `attr.rs` stops the *focus*, but the
-  press frames are still being handled by the field rather than passed
-  to the list from the first slop-crossing frame. The `DragGesture`
-  merge (RUST.md's plan box) should make this one mechanism: once a
-  gesture commits to a pan, the list captures it wherever it began.
-- [ ] **"Flinging still does not work."** Expected on this build: finger
-  flings are dropped by per-widget hit testing, which `DragGesture`'s
-  pointer capture (commit `e12c708`, not yet merged at 02:07) targets.
-  Stays open until verified on her phone, not the emulator.
+  after I go past it."** Not closeable from the emulator, annotated
+  2026-09-06 after the `DragGesture` merge. `attr.rs`'s `on_press` never
+  calls `capture_pointer` and never consumes a `Pressing` frame past
+  `DRAG_SLOP` (it just stops watching), so once the finger's *current*
+  position leaves the composer's box and enters the list's, `List`
+  starts receiving ordinary hit-tested `Pressing` frames there --
+  `DragArbiter::is_idle()`'s 2026-09-05 recovery (a missed `PressStart`)
+  picks it up rather than leaving it stuck. What this does **not** do is
+  what "wherever it began" implies literally: `DragArbiter::press_start`
+  restarts from the *boundary-crossing* position, not from the original
+  touch-down inside the composer, so the pan still needs a fresh
+  `DRAG_SLOP` of travel measured from the boundary rather than from the
+  start of the gesture -- composer and list are adjacent, non-overlapping
+  widgets (`lib.rs`'s `(list, composer_bar).span(Dir::DOWN)`), and only
+  the composer forwarding its own drag to the list would remove that
+  residual slop entirely, which is more than this pass's merge changes.
+  RUST.md's merge-pass box has the reasoning in full and an emulator
+  swipe confirming the composer's own box never moves/resizes during it;
+  whether the residual slop is still perceptible as "caught" needs Iris's
+  phone, since the emulator's per-widget boundary is a few dp wide and
+  easy to cross without noticing on a real screen too.
+- [ ] **"Flinging still does not work."** No longer expected to reproduce
+  after the `DragGesture` merge (`e12c708`, pointer capture +
+  `CursorSense::Drop`), 2026-09-06. Emulator evidence (RUST.md's
+  merge-pass box, check (b)): a real `ui-trace` finger swipe followed by
+  screenshot-hash sampling caught a post-release frame distinct from the
+  drag's own last frame in one run, and every run showed 28-32
+  `render()` frames per gesture against an idle baseline of 0 and ~8
+  expected from the drag alone -- redraw kept being requested well past
+  the finger lifting, which only happens while a fling is still
+  animating. Left unticked in spirit until Iris's phone confirms it,
+  since only she can say whether it *feels* like a fling now; the
+  emulator's screenshot timing could not always catch the tail of a
+  fast-settling one visually (same caveat noted in RUST.md).
 - [ ] **"Text still disappears if I leave and come back to the app."**
   The `GlyphAtlas::clear`/`Textures::reset` fix was verified on the
   emulator under `force-gles` only; the phone runs Vulkan. So either the