Semaphore v2.18 replaced the single vault_key_id field with a vaults[]
array supporting multi-vault per template. Sending vault_key_id is
silently ignored — template stores no vault association, runs fail
at the playbook stage with 'Attempting to decrypt but no vault
secrets found'.
Wrap the single configured vault password in the required envelope:
vaults: [{id: 0, vault_key_id: <key_id>, name: 'default'}]
Empirically verified: PUT with this shape returns 204 and the GET
echoes the vault back with a server-assigned id.
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