8b1364d4c2
- Replaced event-driven handoff with one-shot `generateHandoff(...)` via `completeSimple`. - Added cancellable `/handoff` command handling with a loader and Escape-to-abort flow. - Removed legacy `compaction/handoff.ts` exports and added `generateHandoff(messages, model, apiKey, options)`. - Fixed pre-cancelled handoff behavior to return `Handoff cancelled` and propagate abort signals. - Updated handoff tests/mocks to assert `generateHandoff` invocation details and `AgentSession.handoff()` options.