Say what the FFmpeg format tests have actually been run against

R18 / #27. The front-page status line said the FFmpeg format tests "have been
written but not yet executed on a device". They have been executed, repeatedly
and green, and this is the one line a contributor uses to decide whether the
FFmpeg path is trustworthy -- understating it costs more than a stale detail
elsewhere would.

FFmpegEngineTest's nine format tests -- mp3, gif, matroska, flac, wav, opus,
H.264, H.265, and the one asserting a failure surfaces as an exception rather
than a silent empty file -- were present at every commit cited below, checked by
counting @Test in that file at each:

- Physical Pixel 10 Pro XL, API 37, 2026-08-21 at edd6385: 40 / 0 / 0 / 2.
- The audit's own Pixel pass, 2026-08-22: 49 / 0 / 0 / 2.
- Four local emulator levels, API 33-36, 2026-08-22 at 22c7914: 49 / 0 / 0 / 2
  each.

Zero failures in all of them, and the two skips are RealMediaBenchmark's
assumption-guarded tests, not these. CI's e2e matrix in status_check.yml covers
API 33-36 and the workflow triggers on pull_request against main, so "on every
pull request" is checked rather than assumed.

The replacement names the runs instead of a count, since a total is the part
that goes stale -- androidTest has moved 40 to 49 to 57 in a few days. It also
keeps the API 37 caveat visible: no CI row, so that level stays a manual Pixel
check before each release.

Held, not decided here: whether a front-page status line should carry a
verification claim at all. Fixing what it says is separable from deciding what
it should be for.

Gate green: ktlintCheck, detekt, lintDebug.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -6,8 +6,19 @@ compression, audio extraction and conversion, GIF and frame export, and file mer
 Android 13+ (API 33). Built with Jetpack Compose and Material 3.
 
 > **Status: working, unreleased.** Both conversion engines, the router, the background
-> job queue and the join flow are implemented and building. The FFmpeg format tests have
-> been written but not yet executed on a device.
+> job queue and the join flow are implemented and building. The FFmpeg format tests run
+> green on a physical Pixel 10 Pro XL (API 37) and on local emulators at API 33–36, and
+> CI runs the instrumented suite at API 33–36 on every pull request.
+
+*Correction (`R18 / #27`): this line used to say the FFmpeg format tests had "been written but not
+yet executed on a device". That was true when written and stopped being true at the first device
+pass, which nobody came back to update — so the one line a contributor uses to decide whether the
+FFmpeg path is trustworthy understated its own evidence. The nine format tests in
+`FFmpegEngineTest` were in every one of those runs, all of which came back with zero failures;
+they are recorded under "Verified on real API 37 hardware" in
+[`docs/api-37-emulator-crash.md`](docs/api-37-emulator-crash.md) and "The sweep, run" in
+[`docs/local-emulator.md`](docs/local-emulator.md). API 37 has no CI row, because that emulator
+image is broken, so it stays a manual Pixel check before each release.*
 
 ## Licensing at a glance