Improve run log scrolling and current step wording

[afurm]

Summary

• Problem: The task detail Runs tab could make the latest run log hard to reach when several previous runs were visible, and the header Current step strip displayed raw tool progress such as full run_shell (...) completed in ... messages.
• Why it matters: Active task work should stay scannable from the header while preserving technical details for users who open the run console.
• What changed: Bounded the task inspector and run log scroll areas, added independent scrolling for long run logs, and summarized raw tool progress into human-readable Current step text such as "Searching GitHub issues" or "Running tests".
• What did not change: Raw command names, arguments, timings, errors, and technical event details remain available in the Runs log.

Change Type

• Bug fix
• Feature
• Security hardening
• Documentation
• Chore / infrastructure

Security Impact

• New permissions or capabilities? No
• Secrets or token handling changed? No
• New or changed network calls? No
• Local storage or memory scope changed? No
• If any answer is Yes, explain the risk and mitigation: N/A

Verification

• npm audit
• npm run typecheck
• npm test
• npm run build
• npm pack --dry-run
• UI screenshot or recording attached, if UI changed

Additional focused check:

• npm test -- src/client/components/TaskModal.test.tsx

Notes

• Linked issue: Closes Improve run log scrolling and current step status wording #21
• Platform tested: macOS local checkout
• Known limitations: No screenshot attached; coverage is through component regression tests plus the production build.