featureplan-kickoff

VNX feature-execution kickoff preflight. USE THIS when starting or resuming a feature or track from its plan: checking worktree/queue/staging health, finding the first promoteable dispatch, and handing off to @t0-orchestrator. Reads the feature's track + plan doc from Horizon's tracks DB (vnx horizon, alias vnx objective); the repo FEATURE_PLAN.md/PR_QUEUE.md are generic examples, not the source.