fix: restore stable CI execution seams

[Astro-Han]

Summary

Restore the CI-critical seams removed or destabilized by recent changes:

• reset chat scroll and unread state by conversation identity without remounting the live composer draft
• preserve the stable tool-call row slot used by product layout and geometry coverage
• forward the published List accessible name to the rendered list
• make Code Mode concurrency coverage prove overlap with an explicit barrier and accept either valid preemption point at the concurrency limit

This keeps the two-tone shell and stock Astryx composition while restoring the existing Storybook and desktop E2E contracts, and removes scheduler-dependent Code Mode assertions without weakening the concurrency guarantees.

Verification

• CI=true npm --workspace @maka/desktop run smoke:storybook
• focused Playwright specs: activity card sticky, composer skill invocation, and skill draft lifecycle
• npm --workspace @maka/ui test
• npm --workspace @maka/desktop run typecheck
• npm --workspace @maka/code-mode test
• Code Mode full suite repeated 30 times after the deterministic barrier change
• npm run format:check

Checklist

• Tests cover the changes and fail without them
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No