fix(ci): close remaining release-green gaps

[diegosouzapw]

Refs #9737

The full release-equivalent preflight after #9820 exposed two inherited blockers that the fast path did not exercise:

• four legitimate behavior changes had a net assertion reduction against main, so check:test-masking remained HARD red;
• validate-release-green launched check:pack-boot in parallel with check:pack-artifact, allowing the boot smoke to race the creation of dist/server.js on a clean worktree.

This follow-up restores behavior-level assertions without an allowlist, makes the #4165 queue test exercise a demonstrably dispatched callback instead of an OpenAI provider quota wait, and sequences the tarball boot after the artifact builder succeeds.

TDD and validation:

• RED: validate-release-green test proved pack-boot was declared before the parallel artifact build completed.
• GREEN: 54/54 focused tests.
• GREEN: GITHUB_BASE_REF=main npm run check:test-masking; 266 modified, 0 renamed, 2 deleted, no weakening.
• GREEN: focused project ESLint.
• GREEN: npm run typecheck:core.
• GREEN: npm run check:cycles.
• GREEN: concurrent merge-tip test from fix(combo): ignore benign empty error fields in streaming quality validation (502 false-positive on opencode tool calls) #9786, 3/3.

No workflow, suppression, ratchet baseline, or test-masking allowlist was weakened.

[diegosouzapw]

Babysit/review audit complete for head c54024a9f722f024ecad120f7b9fa9047a68fd6c.

Evidence:

• Review conversations: 0 open / 0 total.
• Base sync: release/v3.8.50@13dcbfd1174e430b11217344ac54ef007b50bd86; head is 0 behind.
• Blocking CI: all green, including Fast Production Build, Fast Quality Gates, Vitest, all 4 unit shards, ESLint warning guard, docs/merge-integrity, DAST, CodeQL and Semgrep.
• Build (advisory) is still queued and is explicitly job-level continue-on-error: true in .github/workflows/quality.yml:61-68.
• Local gates: focused 54/54; test-masking exit 0; focused ESLint, typecheck:core, cycles and git diff --check green.
• TDD evidence: sequencing regression test failed before the pack-artifact/pack-boot fix and passed after it.

The scheduled release-green report on issue #9737 remains open because it also reports newer/unrelated release-tip failures; this PR is ready on its own evidence and post-merge release-tip validation will classify the remaining items.