Bridge an already-authenticated portal session into a YAMA web session via
a new /sso endpoint, so portal administrators can enter the remote-desktop
UI without a second login. Only the "admin" portal role is bridged; any
other role (viewer, unknown) still falls back to the built-in login form,
so a low-privileged portal account cannot bypass authentication.
- wsauth: extract IssueToken from VerifyLogin so an out-of-band-authenticated
identity (SSO) can mint a session token without the challenge/response.
- web: add the SSODetector interface, a fail-closed JWT detector (HMAC-only),
and the /sso handler gated to the admin role.
- cmd: enable the JWT detector via YAMA_SSO_JWT_SECRET, the shared HS256
secret matching the parent portal.
- web UI: attempt SSO before showing the login form, falling back to login
when the server returns 401.
- docs: document SSO (admin-only) and license trial-vs-paid troubleshooting
in README and the env example.
Co-Authored-By: deepseek-v4-pro
