compose: rebuild with the fling/stream/type/keyboard bench v2

Iris asked for a faster fling (v1's tween-based swipe barely moved the
list) plus typing and keyboard phases; see ai-app-2's docs/RUST.md P0
box, "Benchmark v2 (2026-09-06)" for the spec and the emulator smoke
run this build was checked against.

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

README.md

@@ -11,6 +11,21 @@ no enrolment and no permissions.
 
 The rest of this file is the runbook that was delivered with the APKs.
 
+**2026-09-06: bench v2 (fling/stream/type/keyboard).** `compose-bench-arm64.apk`
+rebuilt with the four-phase benchmark Iris asked for after using v1 on her
+phone -- a real fling (12,000px/s through the list's own `FlingBehavior`,
+not the old tween-based swipe, so it travels much further per gesture),
+the existing 400-event/20s stream, a type phase (600 fixed characters
+typed into the real composer then deleted, to exercise wrapping and the
+transcript being pushed upward), and a keyboard phase (five show/hide
+cycles). The report gains a `per phase:` block (frames/late/percentiles/
+worst/duration per phase) ahead of the existing whole-run sections, and
+`bench:` gains the fling phase's travel, the typed character count, and
+how many of the ten keyboard toggles were confirmed by the platform. Full
+spec and the emulator smoke run are in ai-app-2's `docs/RUST.md`, P0 box,
+"Benchmark v2 (2026-09-06)". Same steps below still apply -- "Run
+benchmark" is unchanged in name and location.
+
 ---
 
 # P0 benchmark APKs