Jellyfin:ScanLeader:Enabled defaults to false and nothing sets it, so
leader election never runs and every replica executes the timer-driven
library tasks concurrently - the exact behaviour the lease prevents.
- Enable gating by default when a Redis connection string is configured
- Honour an explicit Enabled setting either way
- Carry the effective decision onto the bound options the task worker reads
- Log at startup whether gating is active
- Warn when gating is enabled but no Redis connection string is configured
unkin-agent