The isZh migration was losing ground (12 -> 31 files over 90 days at
filing; 28 today outside web/lib/i18n). Count the files that still
branch on isZh outside the migration home and fail web CI if the number
grows. Migrating branches lowers the count; then ratchet the CEILING.
Signed-off-by: CodeWhale Bot <bot@codewhale.net>
Co-authored-by: CodeWhale Bot <bot@codewhale.net>