jwks_uri from the OIDC discovery document is fetched without checking its origin or scheme

PIA's token verification (`verify_token` in `pia/oidc.py`) fetches the OIDC discovery document of an allowlisted issuer and then follows the `jwks_uri` contained in that response without parsing it as a URL, comparing it against the approved issuer's origin, or requiring HTTPS — the only check is that the field is non-empty (`pia/oidc.py:42-52`). An approved identity provider — and every registered per-project Jenkins instance under `https://ci.eclipse.org/<project>/oidc` is a separate such party (`pia/models.py`) — can therefore direct PIA to issue a GET request to an arbitrary host and port, including over plaintext `http`, from PIA's own network position. The fetch happens before any signature is verified, as a side effect of an unauthenticated `POST /v1/upload/sbom` request that is ultimately rejected with 401.