0eda57fa

By: Michael Lynch <git@mtlynch.io>

Use generic rate limit error in login handler

Replace shared_secret.ErrRateLimited with ratelimit.ErrLimitExceeded so
the login handler no longer imports the auth implementation package.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
configuredevShellbackendbackend-devcheck-bashcheck-frontendcheck-go-formattingcheck-go-test-packagescheck-trailing-newlinecheck-trailing-whitespacediagramdocker-imagee2e-testsgo-testsimport-from-tinybeanslint-sqllittle-momentslittle-moments-devx86_64-linux