Registry now reads `[shared].token` and `[registry].bind_addr` from the
unified file via maestro-config. First-run token generation does a
read-modify-write so `[shared]` / `[cli]` / `[daemon]` sections that
already exist on a co-located host stay intact.
Env-var renames:
- MAESTRO_TOKEN → MAESTRO_SHARED_TOKEN
- MAESTRO_REGISTRY_CONFIG → MAESTRO_CONFIG
`MAESTRO_REGISTRY_BIND_ADDR` is unchanged. The startup banner now points
the operator at `MAESTRO_SHARED_TOKEN` when announcing a freshly
generated token.
e2e harness updated to use the new env var; auth.rs doc-comment updated
to reflect the new env-var name.
naps62-yolo
ed5743cd50