Address Section-1 second-opinion findings (6 reviewers): - redact bearer tokens greedily and case-insensitively, hoist the pattern, and route the onError response-data debugPrints through the same helper - detect browser cancel via flutter_web_auth_2's typed PlatformException CANCELED signal scoped to the authenticate call, so server-controlled callback text can never be reclassified as a user cancel - convert ArgumentError from malformed percent-encoding into catchable FormatException; handle ArgumentError in the login screen catch chain - sanitize attacker-influenceable error/error_description (control chars, 200-char cap) before they reach exception messages and Sentry - rethrow SignInCancelledException in AuthProvider without recording an error state - getComments: omit empty parentRkey - tests: real capture-based redaction coverage (replacing the inline-regex fake), error-over-token precedence, malformed-callback, parentRkey wire serialization, and retry-exhaustion assertions Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>