## Summary

Keep foreground-work measurements and per-window presentation
expectations valid across observed sleep/wake and visibility changes.
Simplified after review to about 530 changed lines including tests and
configuration.

## Scope

- Keep all measurement state in the foreground-local journal writer. Use
`PowerState` and `PowerTransition`; no new locks, counters, or changes
to the ring protocol.
- Work that started at or before the last power transition (or while
suspended) is dropped when it completes: task polls before small-poll
folding, and actions, inputs, draws, and presents through the same
`power_interrupted_since(start)` check. No per-activity state is added;
every measurement already carries its start time.
- Track visibility and pending frames together per window. Hiding or
sleeping clears the presentation expectation; on recovery
`Window::refresh_visibility` re-records it from the window's actual
dirty state, so the journal never guesses. Old latency associations
remain invalid.
- Repeated notifications for the same power state are ignored, so a
duplicate wake does not invalidate in-flight work.
- The journal subscribes to GPUI's existing power notifications and
rechecks native window visibility after wake. App only registers these
subscriptions (two initialization lines).
- Keep the existing one-second pending-frame deadline and
foreground-turn sealing behavior. No watchdog, recurring timer, test-app
exceptions, unfinished-hang detection, start/end ring notices, or
reader-side deduplication.
- Remove lifecycle counters. Keep measurement version 2 on reports and a
valid dirty-to-present sample count for weighting averages.

## Telemetry

- `Hang Incidents` gains `report_window_seconds` and stall percentiles
over every incident in the window (`stall_p50_ms`, `stall_p95_ms`,
`stall_max_ms`, from an `hdrhistogram`), so stall distributions no
longer depend on the censored `incidents[]` list. Reports are now sent
even when no incident occurred, so summing `report_window_seconds` gives
observed running time for incident rates.
- `Frame Duration Report` gains dirty-to-present percentiles
(`dirty_to_present_p50_ms`, `dirty_to_present_p95_ms`,
`dirty_to_present_max_ms`) alongside the existing average, and
`average_present_interval_ms` (mean frame-to-frame interval while
animating, a proxy for the display's refresh interval when normalizing
dirty-to-present).

Detection remains completion-based. This does not solve hangs that never
return or force an interval to seal when no further foreground events
arrive. Existing legacy hang logs/trace triggers are unchanged. Late or
coalesced platform notifications remain a coverage limitation.

## Validation

- `corgi test -p gpui --features profiler --lib`: **392 tests passed**.
- Focused lifecycle/wake tests also passed a 20-seed run.
- The extension-suggestion regression that failed on all three CI
platforms now passes locally after removal of the
watchdog/test-construction changes.
- `corgi check -p gpui` and `corgi check -p zed -p input_latency_ui`
passed.
- Formatting and `git diff --check` passed.
- Corgi configuration includes only the three existing GPUI image/font
fixtures needed to run its tests.

Native platform sleep/wake testing and review remain outstanding. The
README review marker remains for the human author to remove manually
after review.

Release Notes:

- Improved the accuracy of hang and frame-latency telemetry around
sleep, wake, and hidden windows.
- [GPUI] Added a `PowerTransition` interval boundary and
`measurement_version` to profiler hang reports.