fix: sync restart QA DAG assertion into v0.9.10

[numnx]

What changed

• sync the restart-aware QA DAG assertion fix from dev into release/v0.9.10
• preserve exact QA outcome validation while accepting repeated rejection only when durable recovery and a distinct repair completion prove a valid restart cycle
• keep canonical and public testing documentation aligned

Why

The Linux Docker DAG completed correctly across forced restarts, but the test harness rejected a valid changes_requested, changes_requested, pass history. This sync fixes that false negative without weakening protection against spurious or reordered QA histories.

Validation

• pnpm exec vitest run tests/backend/ci/workflow-health.test.ts tests/backend/scripts/mockup-sprint-pentest-runner.test.ts — 46 passed
• pnpm run lint — passed
• pnpm run check:docs-web — passed
• pnpm run build — passed
• source PR fix: harden restart QA DAG assertions #3159 passed the complete local CI suite and all applicable GitHub jobs, including Linux Docker, Windows Electron, and macOS Electron DAG lanes

Risk and rollback

Risk is limited to the mock sprint pentest assertion layer. Roll back commit 1339a09b9 if the stricter causal matching rejects a newly discovered valid recovery history.