The bottom-left settings button and the settings page both read
profilePictureUrl, but only the settings page had a fallback (initials
avatar) - the button silently fell back to a gear. The URL itself was
usually null because fetchProfilePicture raced the background OAuth
avatar sync with a fixed 500ms delay and never retried, and a missing
bucket object simply resolved to null.
- useConfigButtonIcon: fall back to the same initials avatar as the
settings page instead of the gear when no picture URL is available.
- UseSession: fetch the profile picture when syncOAuthAvatar settles
(init and SIGNED_IN) instead of after an arbitrary 500ms.
- fetchProfilePicture: when the bucket copy is missing, fall back to
the OAuth provider's own photo URL so the picture shows immediately
on first login - unless the user explicitly uploaded/removed a
picture (metadata source 'upload'), preserving the remove flow.