Up to six more test/[p-s]*.test.ts files join the gate, each proven green three times under the gate's load #1141

Pillar: P0 Trust (umbrella #586), part of #261. This replaces #563. Its two tries failed: one timed out on 33 files, and one failed on the studio test that was red on main. One run cannot finish the whole range, so this issue admits a few files at a time.

Intent. The gate covers more of the code, and no file joins until it has shown it holds up under load.

Range (reason: "not yet admitted" today): pacing.test.ts, palette.test.ts, parity.test.ts, policy.test.ts, probe.test.ts, probes.test.ts, prompts.test.ts, public-url.test.ts, push-through.test.ts, qr.test.ts, read-api.test.ts, revert.test.ts, reviews-states.test.ts, reviews.test.ts, runs-lease.test.ts, scaffold.test.ts, search.test.ts, secret-store.test.ts, security-merge.test.ts, security-xss.test.ts, signin-throttle.test.ts, snapshot-destination.test.ts, snapshot.test.ts, spawn-placement.test.ts, sse.test.ts, ssh-app.test.ts, ssh-port-taken.test.ts, ssh.test.ts, standards.test.ts, studio-phone.test.ts, subscriptions.test.ts.

Done looks like.

• [ ] Pick up to six files from the range, the fastest first (scripts/test-times.json). Run each one three times with FORGE_CHECK_SHARDS=1 bun scripts/test-shards.ts --timeout 60000 together with the gate. Only a file green all three times moves from EXCLUDED to GATE. Put the three results in the pull.
• [ ] A file that comes back red stays in EXCLUDED, with reason: "red: <the failing case>" and #261 as its owner. Its test is not edited.
• [ ] The pull's own check is green, and the gate's wall time stays under the check's timeout. Put the before and after times in the pull.
• [ ] test/check-list.test.ts stays green, and nothing outside scripts/gate.ts (and scripts/test-times.json if needed) changes.

Risks. Bringing a flaky file into the gate that every pull then pays for. The three-run rule is there to prevent that. The rest of the range stays with #261 for the next sweep.

Suggested: mason or sentinel.