- Soften the OAuth-callback-rejected toast: the shape guard is
defense-in-depth, not full CSRF prevention (PKCE remains primary), so the
message no longer overstates ("rejecting to prevent a cross-site request" ->
"did not originate from this session").
- Document the intentional asymmetry between a present-but-malformed `state`
(rejected) and a wholly absent `state` (accepted, matched via
OAUTH_PENDING_SERVER_KEY) — rejecting the null case would mask real provider
error redirects that omit `state`.
- Make the "valid state is not rejected" test assert the specific downstream
"could not be matched" toast (seeding OAUTH_PENDING_SERVER_KEY) instead of an
indirect "some toast fired" check.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S3fTN8H3R8YV4yUGvZjYnX
d21da16983