Keep OASIS alive for Interview and Survey before report generation

[killernay]

Problem\nAfter simulation actions complete, the UI/report flow can close OASIS before Interview Agent and global survey run. is irreversible for that run, so Interview fails and report loses interview evidence.\n\n## Required flow\n\n\n## Scope\n- Permit interview and report generation while the run is in awaiting-finish and OASIS is alive.\n- Do not auto-close OASIS or auto-start report before interview/survey.\n- Expose an explicit lifecycle/preflight status so UI disables Finish while interview/report work is active.\n- Unlock Interview based on live environment readiness, not only completed report.\n- Keep explicit confirmation for final close.\n- Add backend/frontend regression tests for awaiting-finish, alive/dead environment, interview, report, and close ordering.\n\n## Acceptance\n1. A completed simulation remains interviewable until explicit Finish.\n2. Interview and survey requests fail early with a clear localized error if OASIS is not alive.\n3. Report generation can use live verified interview evidence before close.\n4. Finish/close is blocked while interview/report tasks are active and requires confirmation.\n5. No extra simulation/LLM run is needed to validate the lifecycle changes.\n