* fix(auth): map malformed OIDC provider bodies to OIDCError
The SSO login route answers OIDCError with 502 and the callback with
an sso_failed redirect, but oidc.py raised OIDCError only for transport
and HTTP status errors. A provider answering 200 with an HTML page or
any non-object JSON raised JSONDecodeError, KeyError or AttributeError
instead, so both routes failed with a 500. A malformed UserInfo body
also aborted the login, although UserInfo is best-effort.
Decode discovery, token, JWKS and UserInfo bodies through one helper
that requires a JSON object, require string endpoints and issuer, reject
a non-list JWKS keys field, skip non-object JWK entries, and wrap a
malformed ID token header as OIDCValidationError. Build discovery
metadata before caching it so a rejected document is not served from
the cache.
* docs(changelog): reference #7258 for the OIDC malformed body fix
* fix(auth): report a falsy non-string OIDC issuer as wrong-typed
Check the issuer's type before its presence so 0, false and [] get the
non-string message instead of "missing the issuer field"; an absent or
empty issuer still reports missing.
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
