Drop form-action from the default Content Security Policy on the OAuth
consent page. Chrome enforces form-action across the entire redirect
chain, which breaks flows where an HTTPS callback internally redirects
to a custom scheme (e.g. claude://, cursor://). Since the form posts
to itself and all redirects are server-controlled, form-action adds
no security value here.
Also forward the consent_csp_policy parameter through all concrete
OAuth providers (Auth0, Azure, Google, GitHub, Discord, WorkOS, AWS
Cognito, OCI) so users can override the CSP without accessing private
attributes.
