Resume hint reprint in outer terminal (S6)

[JRedeker]

Summary

When an OpenCode session ends or hibernates, print a resume hint in the outer terminal (the tmux window or shell that launched opencode) so the user knows how to reattach.

Why

Currently when a session ends, the terminal goes blank. Users forget the attach command and start fresh sessions, accumulating stale sessions.

Acceptance Criteria

• On session exit/hibernate, print oca attach <session> to outer terminal
• Works in both tmux and non-tmux environments
• Hint includes session name and project path
• No hint if session was explicitly killed

Proposal

docs/proposals/2026-05-04-oca-resume-hint-outer-terminal.md

WSJF Estimate

Value: 4 | TC: 3 | RROE: 4 | Effort: 3 | WSJF: 1.8