Gmail's restricted https://mail.google.com/ scope needs a paid CASA assessment to ship a
public release, so a dedicated Google OAuth button is a dead end. Drop it from the setup
screen — Gmail is still reachable via "Other (IMAP/SMTP)" with an app password.
- Removes the Google button and its now-unused launcher, coroutine scope, imports, and
strings. The setup screen now offers Microsoft and Other (IMAP/SMTP).
- The underlying Gmail OAuth plumbing (GmailAuthManager, addGmailAccount, the ViewModel's
Gmail methods) is left intact but unexposed; it can be ripped out entirely or re-surfaced
later. assemble/lint/test green; verified on the emulator.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>