ci: run media-use tests when media-use changes

[miguel-heygen]

Runs the skills test job when packaged media-use code or its parity test changes. The runner already selects those tests; the path filter was the missing route.

On head 0adfec6960ccc0219892f2c48c02f5b2ccab8367, CI printed both reachability reports. Counting their entries confirms 83 findings across 45 files before, and 7 findings across 7 files afterward. All 76 media-use filter findings are gone.

Base report excerpt (one of the 38 media-use files):

{
  "packages/cli/src/media-use/lib/adopt.test.mjs": [
    "CI filters exclude packages/cli/src/media-use/lib/adopt.test.mjs (for example packages/cli/src/media-use/lib/adopt.test.mjs)",
    "CI filters exclude packages/cli/src/media-use/lib/** (for example packages/cli/src/media-use/lib/adopt.mjs)"
  ]
}

Complete head report:

{
  "packages/producer/tests/distributed/_smoke/webm-concat-copy.test.ts": [
    "no CI runner selects this test"
  ],
  "packages/producer/tests/playback-rate-av-parity/playback-rate-av-parity.test.ts": [
    "no CI runner selects this test"
  ],
  "registry/components/pan-stations/pan-stations.test.mjs": [
    "no CI runner selects this test"
  ],
  "scripts/creator-editing-capabilities.test.mjs": [
    "no CI runner selects this test"
  ],
  "scripts/generate-catalog-payloads.test.ts": [
    "no CI runner selects this test"
  ],
  "scripts/generate-catalog-previews.test.ts": [
    "no CI runner selects this test"
  ],
  "scripts/registry-primitive-payloads.test.ts": [
    "no CI runner selects this test"
  ]
}

Focused CI output:

# tests 25
# pass 25
# fail 0
Test reachability verified: 7 baselined test files.

Based on main after the reachability gate merged. The seven unselected tests are wired in #4260; #4261 removes the baseline. No test assertions or application behavior change. Draft until full CI and independent review pass.

[jrusso1020]

APPROVE at 673f3c40

Small, correct, and every number in the description reproduces. I ran the gate rather than reading it.

The claims, re-derived independently

I checked the base (86e27b00, which is #4257's merge) and the head out side by side and ran scripts/check-test-reachability.mjs --report in each:

BASE  files: 45  findings: 83
HEAD  files:  7  findings:  7
files that CLEARED: 38   files ADDED: 0
  of which media-use: 38   non-media-use cleared: []
  findings removed from media-use files: 76

That is the description's "83 findings across 45 files before, and 7 findings across 7 files afterward" and "all 76 media-use filter findings are gone", to the entry. I also parsed the two JSON blocks out of the PR body and compared them to my own runs: the complete head report is byte-identical to what the checker prints here, and the base excerpt for adopt.test.mjs matches my base report for that file exactly. node --test scripts/check-test-reachability.test.mjs gives # tests 25 / # pass 25 / # fail 0, and the gate itself prints Test reachability verified: 7 baselined test files. — both the same strings the description quotes.

files ADDED: 0 is the one I most wanted to see. Shrinking a baseline by 38 entries is only safe if nothing regressed into it while you were looking; nothing did.

The premise holds: the runner was already there, only the route was missing

test-skills discovers its set with find skills packages/cli/src/media-use -type f -name "*.test.mjs" and then appends scripts/check-media-use-copy-parity.test.mjs explicitly (ci.yml:427, :432). So both paths this PR adds to the skills filter are inputs the runner already selects — the job just never fired for them, because packages/cli/src/media-use/** wasn't in the filter. The two additions match the runner's inputs exactly, with nothing left over: the parity test reads skills/media-use/scripts/lib and packages/cli/src/media-use/lib, and the first of those was already covered by skills/**.

Red-greened in both directions

arm	change	gate
A honest head	—	green, 7 baselined test files
B revert the two filter lines, keep the 7-entry baseline	the route removed	red, exit 1 — all 38 media-use files reappear
C keep the filter, restore the 83-entry baseline	the baseline left stale	red, exit 1 — lower baseline to 0 ×38

Arm B is what makes the baseline shrink load-bearing rather than cosmetic. Arm C is the more interesting one: the baseline is an exact set, not a ceiling, so a future fix that clears a violation is forced to delete its entry in the same commit. That is precisely the property a ratchet like this usually lacks, and it means the gate can't quietly stay slack where a regression would recur.

Three things to know, none of them blocking

1. "Both review marks recorded" is not true at this head. pulls/4259/reviews returns 0, pulls/4259/comments returns 0, and issues/4259/comments is []. Mine is the first mark on this PR. Flagging it because it's the second time this week a lane message has carried that line ahead of the reviews existing, and a stamp requested on the strength of it is a stamp requested on nothing.
2. The description still says "Draft until full CI and independent review pass." isDraft is false. Stale line rather than a defect, but it reads as a self-imposed hold that isn't in force.
3. Neither job involved is a required check. The main ruleset requires Semantic PR title, Test: runtime contract, Typecheck, Build, regression, Test, Render on windows-latest, Tests on windows-latest, Studio and player captures — Test reachability and Test: skills are both absent. So this routes the media-use tests into a job that runs but cannot block a merge, and it tightens a gate that is advisory today. Strictly better than the status quo either way; worth knowing the protection is weaker than "these tests now guard the code" sounds.

Nit, and only that: the new Report base reachability step is a diagnostic living in the same job as the gate, with no continue-on-error. It can't misfire on findings — I confirmed --report exits 0 even with all 83 present — and fetch-depth: 0 is already on that checkout, so $BASE_SHA will resolve. Combined with the job not being required, the exposure is about nil. Mentioning it only so the next person who adds a step there knows the pattern.

No test assertions or application behaviour change, as the description says — I diffed both files and that holds.

— Rames