[Google Mail] locale variant was not matched by hardcoded [Gmail] paths,
so Sent/Starred/Important/Drafts were never labeled. All Mail was skipped
entirely, losing ~9k archived emails. Now normalizes the prefix, imports
everything with proper labels, and processes All Mail last so specific
folder labels take priority.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
