fix(cli): propagate caller cancellation through lifecycle orchestration #2151

Summary

PR #2139 makes caller cancellation terminal in the engine-version query, but the CLI orchestration does not propagate a cancelable invocation context into that query.

Current behavior

At reviewed head 7a4ba460d5950333b6a0b60efd6234e1d64dbf81, cmd/main.go:382 creates context.Background(). cmd/multi_service.go:764 also invokes queryMajorEngineVersions with context.Background(), then converts any query error into an empty lifecycle map. cmd/multi_service_helpers.go similarly warns and substitutes an empty map on query failure. The query's repaired cancellation contract therefore does not establish CLI-wide SIGINT cancellation handling.

Steps to verify

Trace the command context through the CSV and recommendation paths to queryMajorEngineVersions. Exercise a canceled parent context with realistic local SDK fixtures and assert that orchestration stops instead of treating missing lifecycle data as a completed query. No live purchase is needed.

Expected behavior

Propagate a cancelable invocation context to API fan-out and treat caller cancellation/deadline expiry as terminal at orchestration boundaries. Keep deliberately recoverable provider errors separate.

Proposed fix

Reuse the existing shutdown/signal handling in cmd/multi_service.go when threading the invocation context from cmd/main.go into the CSV and recommendation paths. Review filterAndAdjustRecommendations and the lifecycle query caller in cmd/multi_service_helpers.go before changing signatures. Add failing-first tests through those actual paths for cancellation, deadline expiry, and active-context provider errors.

Severity: medium. References: #1325, PR #2139. This is an existing orchestration gap, separate from the narrowly repaired query function.