Let a signed-in user turn their own machine into a worker without the
shared token. The coordinator already binds a JWT-authenticated
registration to owner_id as untrusted; this adds the missing pieces.
userservice: long-lived worker keys (scimesh_wk_live_*, hash-at-rest)
with create/list/revoke and a public /worker-tokens/exchange that trades
a key for a short-lived JWT carrying the owner current role/verified.
python worker: SCIMESH_WORKER_KEY + SCIMESH_USERSERVICE_URL; a token
provider exchanges the key and refreshes the JWT proactively and on 401,
so a long-running worker survives token expiry. Static bearer token path
is unchanged.
coordinator UI: an "add your machine" page that mints a key and shows a
ready-to-run command, proxying key management to the userservice; the
dashboard gains an owner-scoped "my machines" section.
docs: how to run a worker from your account, plus the untrusted/quorum/
verified trust model.
Emil