fix(subagents): keep compact results status-only

[tt-a1i]

Summary

• make compact subagent_wait results show only bounded settlement rows and an expand hint
• apply the same status-only projection to automatically delivered subagent results
• keep full child reports unchanged for the parent model, full display mode, Ctrl+O expansion, and /subagents transcripts
• update /openpi-setup guidance, status output, README, and SETUP documentation

Closes #37

Validation

• bun run check
• bun run test (Node 726/726, Vitest 29/29)
• Impeccable detector on the changed TUI renderers: no findings

TDD evidence

• RED: wait preview exceeded the status-only line bound and exposed report text
• GREEN: wait preview renders status rows plus the expansion hint only
• RED: automatic compact result rendered the child report inline
• GREEN: automatic compact result hides the report while expanded mode still renders it