FileStorageService.requireAuthenticatedUser and
FolderService.requireAuthenticatedUser authorize via
'principal instanceof User', but EnhancedJwtAuthenticationToken extends
JwtAuthenticationToken whose principal is the decoded Jwt - so every
/api/v1/storage/* request 401'd for JWT users AFTER Spring Security had
already authenticated them. This persistent 401-with-valid-session was
the trigger feeding the frontend login loop.
Attach the filter-resolved local User as the token principal for full
accounts (User implements UserDetails, matching the form-login
convention every shared instanceof check expects). Anonymous sessions
keep the raw Jwt principal, preserving their existing exclusions. All
other principal consumers verified safe: AuthenticationUtils checks
instanceof User first, extractSupabaseId/CreditController/Team
SecurityExpressions switch on the authentication type, not the
principal.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
