perf(cli): isolate console message input state

[codeaholicguy]

Summary

• move the controlled message draft from ConsoleAppShell into ChatInput
• keep focus, Escape clearing, submit/cancel clearing, multiline layout reporting, narrow layout, polling pause, and keyboard routing intact
• add an Ink regression test proving typed characters render without rerendering the parent

Validation

• npm test --workspace packages/cli — 80 files, 965 tests passed
• npm run lint --workspace packages/cli — exit 0 (5 pre-existing warnings)
• npm run build --workspace packages/cli — exit 0, 193 files compiled
• npx ai-devkit@latest lint — all checks passed

Risks

• None known.