#361 feat(compute): status prints the last deploy/build failure reason

Refs InsForge/instacloud-platform#646 (platform side: InsForge/instacloud-platform#647).

insta compute status now prints the reason when the newest deploy attempt failed. When the failure came from a build, it also prints the command to read that build's logs:

compute app: desired=running  live=none
last deploy failed 2026-10-08 09:34 UTC: insta-compute deploy: the compute plane failed this deploy on routed port 8080: …
  → insta build logs 6a20f7bb-… --source github

--json passes the platform response through unchanged. An older platform that doesn't send lastFailure gets the same output as before.

Tests: test/compute-status.test.ts (new); full suite passes with 3934 tests.

🤖 Generated with Claude Code

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Summary by cubic

insta compute status now prints the reason the newest deploy attempt failed instead of leaving live=none unexplained, and shows the insta build logs command when the failure came from a build.

--json output passes the platform response through unchanged, and older platforms that don't send lastFailure get the same output as before.