ci: validate alpha17 companion against the corrected accessibility core

[mattheliu]

Pins assembled-browser CI to immutable core candidate dsh-v0.1.7-alpha.1-a11y.4 (0f8480ec06), including the catalog keyboard fix and Windows test-constraint follow-up, and updates both compatibility records without rewriting earlier evidence.

Local validation: the unchanged companion implementation previously passed 234 tests and host/client type checks. After the new pin, all seven baseline-guard tests and the clean-revision assembled suite's five tests passed, including Chromium, Firefox and WebKit, against core 0f8480ec06 and companion 7e45e13.

The prior core candidate's Windows coverage failed a concurrent-request arrival-order assumption and a compiler test's timeout override. The fourth candidate keeps exact request counts, cookie/privacy assertions and schema rejection assertions while correcting those constraints; 112 focused core tests passed. Earlier failed-run evidence is retained in both compatibility records.

No npm publication. Real VoiceOver/NVDA and disabled-developer evidence remains pending. Core PR omdsh-dev/deepseek-harness#4 requires complete remote checks, including Windows coverage, before the matching pair is merged.

[mattheliu]

Verified merge completed

• Core PR #4 merged into baseline/dsh-v0.1.7-alpha.1 as ba2f152e5b02e147c482ec883887a4f698ca2925. Its tree is exactly the tested 0f8480ec06 / dsh-v0.1.7-alpha.1-a11y.4 tree (5ec45b90ebad538317994d6ab6941abd756dd728). The older core master remains unchanged at 073359c4d5.
• Companion PR #28 merged into main as aac6ff34ad0b606332e236b871ae968095497431, following PR Adapt companion and AT tooling to DSH 0.1.7-alpha.1 #27. Its tree is exactly the tested 7e45e13 tree (57d810f2e957d4d5e294e450958b19daec22343f).

Before either final merge, core CI had 25 passing checks, including both Linux and Windows coverage, with no pending/failing checks. Three scope-conditioned jobs were skipped: upstream issue policy, Cloudflare preview and credential-dependent real-API E2E. Companion CI passed all eight checks. Neither PR had unresolved review threads; both exact heads and bases were rechecked before squash merge.

The final core Linux instrumented run passed 33,723 tests with one expected failure and 121 conditional skips; its per-file coverage and uninstrumented-heavy gates passed. Remote Web replay passed 488 tests with 13 conditional skips. Final local follow-up evidence includes 112 focused core tests and five assembled external-plugin tests across Chromium, Firefox and WebKit. Earlier failed runs remain recorded separately.

Both local worktrees are clean. No npm publication was performed. Real VoiceOver/NVDA and disabled-developer observations remain pending; these automated checks are not an accessibility certification.