RUST.md, IRIS.md, IRIS_TODO.md, DECISIONS.md: record I5's Android integration and measurements

I5's transcript screen now runs on-device against a real ai-server on
iris-android-app's new transcript-screen feature (extends I2's shell
rather than a third one), with real scrolling, real touch-drag panning
and tap-by-name accessibility all confirmed by screenshot/log evidence.
I4's own emulator-side check (tap-by-name on the tabs demo) closed the
same session, so its box ticks [x] now.

Still [~], not [x]: the render-time number RUST.md's recommendation
wants for iris couldn't be produced this pass, for a precise and
recorded reason rather than a vague one -- dumpsys gfxinfo cannot see a
SurfaceView's own GPU-drawn frames at all (0 frames reported across a
gesture loop that visibly scrolled), and a SurfaceFlinger --latency
fallback gave no per-frame history either on this Android version. The
Compose side of the same loop did produce a real number under identical
conditions (8.96% janky, 99th percentile 150ms), so this is now a
one-sided number rather than a missing one on both sides.

Also found and recorded: the AVD's saved snapshot carries a GPU config
across restarts, so switching between the documented Vulkan boot
recipes needs a cold boot (clearing snapshots/) that the emu wrapper
does not force -- cost three different-looking crashes before the
pattern was the snapshot, not the code.

DECISIONS.md's DEFERRED item is updated with the numbers Iris needs to
weigh the iris-vs-Masonry call; the call itself stays hers.

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

docs/DECISIONS.md

@@ -22,9 +22,31 @@ marked **DEFERRED** are ones the agent chose not to decide alone.
   pinned CA is a path given on the command line, not baked in. Chosen so
   the phone and desktop share one enrolment format and no second one is
   invented.
-- **Order of remaining work**: finish the two in-flight pieces above, then
-  the transcript screen's Android integration and the `transcript-bench.sh`
-  comparison against Compose — the numbers the recommendation still lacks.
-- **DEFERRED — whether to commit to iris over Masonry for `ai-app`.** Waits
-  on the bench numbers above; RUST.md's recommendation says what the
-  measurements must show.
+- **I5's Android integration extends `iris-android-app` (I2's shell)
+  behind a Cargo feature (`transcript-screen`), rather than a third
+  shell crate.** That project already has the Gradle module, the
+  `IrisView`/`MainActivity` Java, and the JNI registration; the only
+  thing a second screen needs on top is a different `AndroidAppState`,
+  the same axis `tabs_ui::build`/`transcript_ui::build` already vary
+  along on the winit side. `tabs-screen`/`transcript-screen` are
+  mutually exclusive and each pulls in only its own deps, so the plain
+  tabs build (I2/I4) is untouched.
+- **Order of remaining work, updated 2026-09-05**: the two in-flight
+  pieces and I5's Android integration are all done; next is giving iris
+  its own frame-timing report so item 3 below can be decided by a number.
+- **DEFERRED — whether to commit to iris over Masonry for `ai-app`.**
+  Updated 2026-09-05 with what's now known: iris's Android integration is
+  built and confirmed working on a real device (real server, real
+  scrolling, real touch-drag pan, tap-by-name accessibility — RUST.md's I5
+  box), while Masonry's own touch-scroll on Android was already found
+  entirely absent (E2). What's still missing on **both** sides is a
+  render-time number — not because iris doesn't work, but because
+  `dumpsys gfxinfo` cannot see a `SurfaceView`'s GPU-drawn frames at all,
+  so the `transcript-bench.sh`-style comparison this recommendation wanted
+  produced a real number for Compose (8.96% janky, 99th percentile 150ms,
+  same emulator/session) and none at all for iris. The choice in front of
+  Iris: decide now on the structural-plus-functional case already made
+  (iris works end-to-end where Masonry's scroll gesture doesn't exist at
+  all on Android), or wait for iris to grow its own frame-timing
+  instrumentation first so the comparison can be a number rather than a
+  qualitative one. RUST.md's "Recommendation" item 3 has the full account.