test(cli): make the app-anchored serve e2e prove a BOOT, not just a resolution (#12622)

* test(cli): boot the app-anchored serve fixture to a banner, not to a dead child

The two happy-path cases proved `serve` RESOLVES an app-local cluster driver
and stopped there: the fixture driver printed a marker and registered nothing,
so `serve` walked on to `Cluster driver "redis" is not registered` and the
child exited 1 without ever calling `listen()`. Nothing in the repo proved
`serve` BOOTS with one -- swept over 2823 test files, `registerClusterDriver`
occurs in zero of them and `packages/qa/**` holds no occurrence of `cluster`
at all, so the coverage had to be built here rather than dropped.

The fixture driver now registers into the framework's own cluster registry,
handed to it as that package's declared ESM entry, and both children boot
through to a ready banner. `SETTLED` drops both markers: they are printed
mid-boot, so waking on one handed the assertions a process that had not
finished. It now matches only terminal outcomes, and the boot is asserted
through `run.outcome` and the absence of the registry error rather than
through the banner text that woke the run.

`portDriftError()` becomes live on the happy-path runs as a result; the
header note that measured its silence is updated rather than deleted, and
`portContentionError()` stays insurance for the spawn-posture reason that
never depended on the banner.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UjujZN219uFzBhSYfMykCd

* test(cli): state the re-measured death timing rather than the inherited one

The header quoted 5.6s from the card that filed this. Re-measured on
527e050 it is 9.6s, so the file now carries both numbers with the tree
each was taken on, rather than a figure this tree never produced.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UjujZN219uFzBhSYfMykCd

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-litant