docs: tick report hygiene and bench header (commits 7485d78, b8ea723)

Both docs/IRIS_TODO.md's night bullets and docs/RUST.md's queue items
covered by the two client-core/iris-android-app commits above.

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

docs/IRIS_TODO.md

@@ -1091,24 +1091,27 @@ showed, beyond her words:
   `Released(None)`, not a tap (Compose does not deliver a click either).
   Layer-1 test on a flick followed by a down + small drag 150 ms later:
   offset tracks the finger sample-for-sample from the down.
-- [ ] **"The copy report button seemed impossible to hit until I hit the
-  diagnostics one."** Not hit-testing: the button logged `iris bench
-  report: nothing to copy -- run the benchmark first` six times and did
-  nothing on screen. A control that silently declines is the UI_RULES
-  failure "a failure is reported where it happened": Copy report must
-  always copy something -- the diagnostics and the log with a first line
-  saying no benchmark has run -- and never depend on another button
-  having been pressed first.
-- [ ] **"The logs seem way too big to send in this message box, causes a
-  lot of lag."** Two causes. (1) The ring was 1339 lines of `naga::front`
-  / `wgpu_core` / `jni` DEBUG output with 4050 dropped: the ring logger
-  accepts every crate at Debug, and the trace gate (992c472) only covers
-  iris's own lines. The ring must take Debug only from `iris`/`client_core`
-  targets when trace is on, and Info and above from everything else --
-  one filter at the ring, not per callsite. (2) Copy report appends the
-  whole ring. It should append the last ~150 lines and a first line
-  saying "N earlier lines omitted; full log in Dev Updater's Runtime
-  tab" -- the full ring is what the devlog provider is for.
+- [x] **"The copy report button seemed impossible to hit until I hit the
+  diagnostics one." (done 2026-09-07, b8ea723).** Not hit-testing: the
+  button logged `iris bench report: nothing to copy -- run the benchmark
+  first` six times and did nothing on screen. A control that silently
+  declines is the UI_RULES failure "a failure is reported where it
+  happened": `copy_report` now always copies something -- the
+  diagnostics pane's own text (with a first line saying no benchmark has
+  run) when nothing has run yet, or the last report otherwise -- and
+  never depends on another button having been pressed first.
+- [x] **"The logs seem way too big to send in this message box, causes a
+  lot of lag." (done 2026-09-07, 7485d78 + b8ea723).** Two causes. (1)
+  The ring was 1339 lines of `naga::front` / `wgpu_core` / `jni` DEBUG
+  output with 4050 dropped: the ring logger accepted every crate at
+  Debug, and the trace gate (992c472) only covered iris's own lines.
+  `client_core::log_ring::ring_accepts` is the one filter now, applied at
+  the ring rather than per callsite: Debug/Trace only from `iris`/
+  `client_core` targets when tracing is on, Info and above from
+  everything else. (2) Copy report appended the whole ring; it now
+  appends `LogRing::tail_text(COPY_REPORT_TAIL_LINES)` (150, named at the
+  constant) with a first line saying how many older lines were left out
+  -- the full ring is still what the devlog provider hands Dev Updater.
 - [x] Keyboard: the report shows `ime_bottom=891 ime_visible=true` then
   back to 0 on the phone, so the insets now arrive with a height; the
   push-up was not reported broken this time.