Ensure skill (config-as-code converge)

Idempotently converge a repo-defined skill (SKILL.md manifest) onto the platform. Identity is name + account scope. Hash-only probes skip the payload in the steady state (a miss is a normal 200 definitionRequired response, not an error); full requests create the skill or append a new version when the canonical content hash differs. The response always carries the server-computed canonical hash + the version id. Set dryRun to plan without writing (CI drift gate), onConflict: “overwrite” to converge over dashboard/API edits, and release: “publish” to publish the converged version. Optional version.label / version.notes stamp provenance (a git SHA, a release tag) on the appended version row. Admin/control plane only — no review queue.