fix(interview): repair interview-history endpoint + show past interviews in Step 5

[alreadyhavefeel]

Summary

The interview-history capability already exists — interviews are written to each platform's OASIS SQLite DB and POST /api/simulation/interview/history reads them back — but it was broken in two places, so past interviews never appeared in the UI.

Bug 1 — backend endpoint crashes on mixed-type timestamps

SimulationRunner.get_interview_history merges twitter + reddit results and sorts by timestamp. The two platform DBs store created_at with different types (one comes back int-like, the other a datetime string), so the sort raises:

TypeError: '<' not supported between instances of 'int' and 'str'

Any multi-platform history query (the default) 500s. Fix: coerce the sort key to str.

results.sort(key=lambda x: str(x.get("timestamp", "")), reverse=True)

Bug 2 — Step 5 never loads the history

Step5Interaction.vue only kept interviews in an in-memory cache for the current session, so they vanished on reload and the persisted history was never surfaced. This wires it up:

• getInterviewHistory(simulationId, opts) in api/simulation.js → calls the existing POST /api/simulation/interview/history.
• On mount, Step 5 loads the history and seeds the per-agent chat cache: sorted chronologically, the injected interview-prompt prefix stripped for display, and deduped across platforms (the same question is recorded once per platform). Selecting an agent now shows prior Q&A.

Testing

• Endpoint previously 500'd on a run with both platforms; after the fix it returns the full history (verified: 43 records across the interviewed agents).
• Step 5 loads and displays prior interviews on mount; live interviewing is unchanged.

Scope

Backend: 1-line fix in simulation_runner.py. Frontend: additive API helper + a mount-time loader in Step5Interaction.vue. No API contract or schema changes.