test(git-ui): add Git client closeout verification

[oscharko]

Summary

Adds the Issue #1578 closeout package for Epic #1571: deterministic Git client evidence, a capstone packaged-app Playwright flow, a CI-wired evidence checker, and closeout documentation tying #1573 through #1577 together.

Refs #1578

Scope

• In scope: Git Client: Final Verification, Accessibility, Visual Regression, Docs, and Closure Evidence #1578 final verification, evidence/docs, evidence hygiene, lightweight checker/CI wiring, local browser proof, and a UI coverage config repair required for the existing UI coverage gate to produce non-empty coverage.
• Out of scope: new Git product capability, backend mutation routes, provider behavior changes, live credential/provider calls, Qodana/CodeQL policy changes.

Reuse And No-Duplication

• Existing Keiko functionality was inspected before implementation.
• This PR reuses, extends, generalizes, or consolidates existing functionality where practical.
• Any new implementation is limited to a documented capability gap in the linked issue.
• This PR does not introduce a parallel workspace, graph, relationship, policy, evidence, memory, connector, workflow, or UI subsystem where an existing subsystem can be extended.
• Refactoring or consolidation was considered when existing functionality was close but not shaped for this change.

Delivery Board

• Linked issue is in the public Keiko Product Delivery project.
• Linked issue has a valid Parent Epic: #1571 unless this PR updates an epic container directly.
• Linked issue is attached as a GitHub sub-issue of its parent epic so it appears in the correct board swimlane.
• Parent epic is on the board with Classification: Epic, Status: Open Epics, and priority/order set for top-to-bottom implementation sequencing.
• Linked task/card issue is on the board with Classification: Task, Status: In Progress while active, inherited or explicit Priority, and Human Review Required: Yes.
• Project Status is In Progress while work is active, or Done only after merge and closure evidence.
• Project Workflow State is PR Open or Ready for Human Review.
• Owner / Agent, Branch, Pull Request, and Human Review Required are filled.
• Issue label reflects the current state: status: in progress, status: ready for human review, or status: done after merge.
• Autonomous agents did not merge into dev, enable auto-merge, close the issue, or bypass human review unless explicitly authorized by the human maintainer.

Product Impact

• UI or user workflow
• CLI or developer workflow
• Core generation engine
• Evidence, audit, or compliance artifact
• Security or supply chain
• Packaging, release, or npm publication
• Documentation or repository hygiene
• No user-facing behavior change

Verification

Required:

• Required GitHub checks pass before merge.
• Local verification commands or rationale are listed below.
• Reuse/extension/generalization evidence or gap rationale is listed below.

Local verification:

npm run check:git-client-evidence
npm run test:e2e:git-changes-1575
npm run test:e2e:git-branch-sync-1576
npm run test:e2e:git-pr-merge-1577
npm run test:e2e:git-client-closeout-1578
npm exec vitest -- run scripts/__tests__/check-git-client-evidence.test.mjs scripts/__tests__/check-git-delivery-evidence.test.mjs
npm exec vitest -- run scripts/__tests__/check-git-client-evidence.test.mjs packages/keiko-contracts/src/git-repository-agent.test.ts packages/keiko-contracts/src/git-repository-summary.test.ts packages/keiko-server/src/gitRepositoryReads.test.ts packages/keiko-server/src/gitDelivery/agentOperationsRoutes.test.ts packages/keiko-server/src/gitDelivery/syncRoutes.test.ts packages/keiko-server/src/gitRoutes.test.ts packages/keiko-contracts/src/git-sync.test.ts packages/keiko-contracts/src/git-delivery.test.ts packages/keiko-contracts/src/git-delivery-validation.test.ts packages/keiko-contracts/src/git-push.test.ts packages/keiko-contracts/src/git-merge.test.ts packages/keiko-contracts/src/git-pull-request.test.ts
npm run test --workspace @oscharko-dev/keiko-ui -- src/app/components/desktop/widgets/cards/git-client/GitClientWindow.test.tsx src/app/components/desktop/widgets/cards/git-client/GitClientWindow.a11y.test.tsx src/app/components/desktop/widgets/cards/git-client/CommitComposer.test.tsx src/app/components/desktop/widgets/cards/git-client/DiffPane.test.tsx src/app/components/desktop/widgets/cards/GovernedPullRequestCard.a11y.test.tsx src/app/components/desktop/widgets/cards/GovernedMergeCard.a11y.test.tsx
npm run check:git-delivery-evidence
npm run build:packages
npm run typecheck
npm run lint
npm run arch:check
npm run arch:check:negative
npm run check:version-consistency
npm run test
npm run test:coverage:ui && npm run check:coverage:ui
npm run test:coverage:quality

Reuse / gap rationale:

#1578 is a capstone closeout issue, so this PR adds no new Git product capability. The closeout evidence uses the already-delivered Git window, existing /api/git reads, existing Git delivery preview/execute seams, existing PR/Merge panels, and the #1577 typed agent facade. The only code-path repair is coverage-gate hygiene: the UI coverage config now roots at the repo so CI/local V8 coverage produces a scored packages/keiko-ui report instead of an empty 0/0 artifact.

Select only what applies:

• UI behavior manually verified or covered by tests.
• CLI behavior verified with command output or tests.
• Core logic covered by unit, integration, property, or fixture tests.
• Security-sensitive change reviewed for trust boundaries, secrets, external calls, and generated artifacts.
• Supply-chain or package-surface change verified with package, license, lockfile, SBOM, or npm dry-run checks.
• Documentation or Markdown change verified by the repository link check or a targeted local equivalent.
• Release-impacting change verified with pnpm run release:check or an explicit rationale.
• Not applicable items are explained below.

Not applicable rationale:

• No live provider credentials or external provider API calls are required; evidence uses local bare-repository fixtures and deterministic route stubs.
• No npm package publication or release version change is included.
• Qodana is not configured as a separate required gate; configured static/security gates are listed in docs/git-delivery/epic-1571-closeout.md.
• CodeQL branch-policy changes are outside Git Client: Final Verification, Accessibility, Visual Regression, Docs, and Closure Evidence #1578.

Review And Closure

• The PR implements only the linked issue scope.
• Actionable review findings are fixed or explicitly dispositioned.
• Unresolved review threads are resolved before merge.
• Checks are repeated after the latest pushed fix.
• Issue acceptance criteria and closure evidence are updated only where evidence exists.
• The linked issue records reuse, extension, generalization, or new-gap rationale before closure.
• Delivery board status is updated before requesting final maintainer review.
• Use Resolves #1578 only when this PR should close the issue.

Risk Notes

• The Git Client: Final Verification, Accessibility, Visual Regression, Docs, and Closure Evidence #1578 e2e intentionally uses deterministic route stubs for PR/Merge/provider outcomes. It proves the Git-window integration path and evidence hygiene without requiring live credentials.
• The UI coverage config change is gate hardening: it keeps the same test set and V8 provider, but makes the generated coverage artifact non-empty and enforceable from repo-root CI/local runs.