Duplicate-message protection hardened
Follow-up to 0.0.26. Live testing turned up two ways the duplicate protection could still be bypassed, and both are now closed.
- Campaign progress no longer overwrites itself. When more than one run touched the saved campaign data, one could wipe the other's record of who had already been messaged, which could let the same person be messaged twice. Progress is now merged instead of overwritten, so one run's record of who was already messaged is preserved instead of replaced.
- Long delays no longer weaken the guard. Campaigns with a gap longer than three minutes between messages could lose their "already running" protection mid campaign. That protection now stays active for the whole run, at any delay.
The app updates itself, no action needed.