docs/RUST.md: emulator verification results for the keyboard/dp/header fixes

run-bench.sh end to end clean (24/24 swipes, 400/400 events); header
background confirmed by screenshot; the keyboard wipe fix confirmed two
ways (a forced wm size resize and an actual soft-keyboard open, both real
surface_changed triggers, text intact both times).

Also records two things found during this verification and not fixed:
the top button row appears to render a second time, out of place, after
a keyboard-triggered resize, and a tap aimed at the field below can land
on it instead -- and the keyboard diagnostics auto-capture never fired in
this session. Neither is root-caused; explicitly not attributed to this
pass's changes without more evidence, per the standing rule against
blaming ambient failures on your own code without measuring first.

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

docs/RUST.md

@@ -4509,12 +4509,57 @@ device.
       warnings`, zero beyond the pre-existing `tabs-ui` unused-dependency
       and wgpu future-incompat notices), `cargo test --workspace` (all
       passing), `cargo ndk -t arm64-v8a check`/`clippy` for both the
-      `transcript-screen bench` feature set. **Not verified this pass**:
-      an actual emulator run of `run-bench.sh`, a forced-resize
-      before/after screenshot for the keyboard fix, or anything on Iris's
-      real phone -- next agent with emulator/phone time should confirm
-      all three and the two-density crispness check IRIS_TODO.md's unit
-      item asks for.
+      `transcript-screen bench` feature set.
+
+      **Then run on this checkout's own emulator** (x86_64 debug,
+      `--features "transcript-screen force-gles bench"` -- this AVD has no
+      Vulkan adapter under a plain `-gpu host` boot, matching every prior
+      emulator finding in this file): `run-bench.sh` end to end, no crash,
+      `frames=534 janky%=79.03 ... cpu_p50=1.3ms`, 24/24 swipes, 400/400
+      streamed events -- unchanged in shape from prior readings, so the
+      diff cost nothing on the success path. **Header background**:
+      screenshot confirms the `HEADER_SURFACE` panel now sits behind all
+      three buttons (`/tmp/bench-after-run.png` this pass). **Keyboard
+      wipe**: forced a real `surface_changed` two ways -- `adb shell wm
+      size 1080x1900` (screenshot before/after, text intact) and actually
+      opening the soft keyboard via `settings put secure
+      show_ime_with_hard_keyboard 1` + tapping the message field
+      (ui-trace confirmed a real resize, elements moved -547px; keyboard
+      visible in the screenshot, text still fully rendered, not wiped).
+      Both are real evidence the reuse-renderer fix works, though neither
+      is the literal before/after diff this box originally asked for --
+      **still worth a deliberate side-by-side screenshot pair in a future
+      pass.**
+
+      **Found during this same verification, not fixed, needs a follow-up
+      pass**: after the keyboard-triggered resize, the top button row
+      appeared to render a **second time**, well below its real position,
+      inside the transcript's scroll area (same colours/text, unmistakably
+      the same three buttons) -- and a tap aimed at the composer's
+      "Message" field landed on "Run benchmark" instead (a second
+      benchmark run started, visible in logcat as two `iris bench report:`
+      lines from one session). Only seen after a resize with the keyboard
+      genuinely open; the plain `wm size` resize screenshot pair did not
+      show it, nor did the fresh-install screenshot before either resize.
+      **Not root-caused this pass** -- time ran out before isolating
+      whether this is the `Span::DOWN` two-phase draw (LAYOUT.md's
+      provisional-then-real placement) leaving a phase-1 primitive
+      retained somewhere it should have been moved from, something
+      specific to the keyboard's `on_insets_changed` rebuild racing a
+      redraw, or unrelated to this pass's changes entirely (not verified
+      against a build predating this session's commits, so do not treat
+      "caused by this pass" as established -- MACHINE.md's pinned rule
+      about not attributing without measuring applies here too). Also
+      noteworthy: `capture_keyboard_diagnostics` never fired in this
+      session (no "iris keyboard diagnostics" log line) despite the
+      keyboard visibly opening -- `on_insets_changed`'s `ime_bottom` may
+      not be populated the way expected on this emulator/API level, or
+      the duplicate-row state above interfered; **also needs a follow-up
+      pass** before relying on the auto-capture on a real phone.
+
+      **Not verified this pass**: anything on Iris's real phone, the
+      two-density crispness check IRIS_TODO.md's unit item asks for, and
+      the two open items just above.
 
 - [ ] **P1 — session screen parity.** History paging backward (with the
       page-boundary healing `client-core` does not have yet, below),