Refine desktop workspace UX

[ephor]

Summary

• redesign Task Detail around connected chat, diff, changes, runtime, and repository controls
• unify Board, Projects, Mission Control, and Sessions rail with the same compact WebStorm-inspired surfaces
• add agent switching, focus modes, responsive panels, persisted board resizing, task actions, and focused UI coverage
• normalize ACP tool activity so Codex and Claude show commands, paths, and expandable details instead of technical IDs
• dock the live turn indicator above the composer and promote child attention states to the Board review lane

Verification

• npm run lint: passed with warnings only
• npm run build: passed
• desktop Vitest: 83/83 passed
• cargo fmt --all --check: passed
• Rust and protocol tests: 96/96 passed
• React Doctor: no new findings; existing large TaskDetail maintainability warning remains