iris bench: clamped scrolling, faster flick start, platform fonts, enrollment, runtime log (ai-app-2 92985ba)

Rebuilt from ai-app-2 rustify commit 92985ba, against the last delivery
(b47eb73). APK 9,639,224 bytes / libmain.so 7,506,448 bytes, both smaller
from replacing bundled Noto with platform fonts plus a release-profile
tuning pass.

README.md

@@ -415,3 +415,57 @@ reproducible here.
 Still not fixed, and still unrelated: the composer bar's grey background is
 not drawn on this build, so the transcript shows through behind the message
 field.
+
+## 2026-09-07, evening: clamped scrolling, a faster flick start, platform fonts, enrollment, and a runtime log Dev Updater can read
+
+`iris-bench-arm64.apk` rebuilt from ai-app-2 `rustify` commit `92985ba`,
+against the last delivery (`b47eb73`, the fling-curve + keyboard-targetSdk
+build). APK **9,639,224 bytes**, `libmain.so` **7,506,448 bytes** (arm64-v8a
+only) -- both smaller than that build, mostly from replacing the bundled
+Noto fonts with the platform's own (Roboto for body text, Droid Sans Mono
+for code) and a further release-profile tuning pass; docs/RUST.md has the
+full size table.
+
+What changed:
+
+- The list is now clipped to its own box and rows are drawn at both edges --
+  nothing scrolls up behind the header, and there is no blank band at
+  either end.
+- Scrolling is clamped at both ends of the transcript, matching the fling
+  fix from the last build: you cannot drag or fling past the top or the
+  bottom.
+- A released flick now starts at the speed your finger was actually moving
+  at, using the same least-squares velocity estimator Compose itself uses,
+  rather than a slower approximation -- a flick should feel like it starts
+  fast and decelerates, not like it ramps up.
+- The clock that timestamps each touch sample was misdating batched input,
+  which fed wrong numbers into that velocity estimate; it now dates them
+  correctly.
+- Code blocks render in a real monospace font and body text in Roboto --
+  both platform fonts now, not the bundled Noto this build removes.
+- The app enrols itself from the `aiapp://enroll` link -- Dev Updater's
+  Enroll button on this APK's component opens it directly. Diagnostics
+  shows either `enrolled: host:port` or `not enrolled`.
+- The app exposes its own log to Dev Updater: APK component -> log button
+  -> Runtime tab. This needs the updated Dev Updater build on the host to
+  show anything.
+- A "Trace" switch in the bench header turns on a line per input and per
+  frame in that log, for when a report alone isn't enough to say what
+  happened.
+- Several of the invariants this code relies on internally are now hard
+  assertions in this release build, rather than silently-wrong behaviour if
+  one is ever violated.
+
+What to look for:
+
+- The header shows nothing behind it, at either edge of a scroll.
+- You cannot scroll past the top or the bottom of the transcript.
+- A flick starts at roughly the speed of your finger and visibly
+  decelerates, rather than ramping up or holding a constant speed.
+- Code blocks are monospace; body text is not.
+- Opening the keyboard pushes the composer up. If it doesn't, screenshot
+  Diagnostics' `insets:` line as in the last build's report.
+- Dev Updater's Runtime tab (APK component -> log button) shows this app's
+  own lines, once the host's Dev Updater is updated.
+- With Trace on, do a few flicks, then press Copy in the render report --
+  the input log that comes back is what to send back here.