aeb0a57a61
The provider implemented the RFC 7523 §2.1 jwt-bearer authorization grant with an SDK-minted or prebuilt JWT, which no MCP auth extension specifies, and has been deprecated since 1.23.0 in favour of ClientCredentialsOAuthProvider, PrivateKeyJWTOAuthProvider, and IdentityAssertionOAuthProvider. Drop it and its JWTParameters model ahead of v2, with a migration entry mapping each of its modes to a replacement.