Address review: reset Discord pending state on failure/cancel, safe metadata reads

The Discord pending banner now offers Cancel and drops automatically when
the auth provider reports an error, instead of pinning the dialog in a
waiting state after an abandoned or failed browser round-trip. displayName
and avatarUrl tolerate non-string Supabase metadata values instead of
throwing during widget build.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
51b5cdb7f8Dara Adedeji committed on 7/6/2026, 10:42:42 PMparent7452db2

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