fix(calendar-sync): skip overlapping syncs for the same calendar

A timer tick that fired while a calendar's previous fetch was still running launched a second concurrent sync for that calendar, wasting work and racing to write the same org file. The dispatcher now skips a calendar whose status is already syncing and logs the skipped tick.

The sentinel resets the status on process exit, so the skip clears on its own. load-state also clears a stale syncing status left by a crash, so a calendar can't be skipped forever.

0 files changed, 0 insertions, 0 deletions