provision_app_password validated the supplied app password by calling the
OCS cloud/user endpoint with BasicAuth as the *path user_id* (the UID).
Nextcloud keys app-password BasicAuth on the loginName, which differs from
the UID for OIDC-provisioned accounts whose UID is their display name
(UID "Chris Coutinho", loginName "chris@coutinho.io"). Authenticating as
the UID is rejected with HTTP 401 ("App password validation failed"), so
provisioning never completes.
Parse the request body up front and authenticate the OCS validation as the
body's `username` (the Nextcloud loginName), falling back to the path
user_id for legacy callers where UID == loginName. The OCS-returned account
id is still checked against the path user_id (the UID), and the password is
still stored keyed by UID with the loginName alongside.
Note this is not an encoding issue: BasicAuth places the user-id literally
in the header (RFC 7617, no URL-encoding); %20/+/literal-space forms of the
UID all fail — only the loginName authenticates.
Adds a regression test asserting the OCS BasicAuth uses the loginName while
storage is keyed by the UID, plus a backward-compat assertion that callers
without a loginName fall back to the UID.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>