When the source workspace is a fork (`wm-fork-*`), the tarball export now
omits `mode` from triggers and `enabled` from schedules. The trigger update
handler also preserves the existing DB `mode` when both fields are absent
from the request, instead of falling back to the BaseTriggerData default.
This prevents a fork's git-sync round-trip from flipping the parent
workspace's enabled/disabled state when a merge applies the fork's YAML
back to main.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>