Fix Job panel pinboard-count sync when using PinAll

[moijes12]

The Job panel pinboard-count was getting out of sync when using the "Pin All" button because it wasn't correctly accounting for already pinned jobs and wasn't allowing partial filling of the pinboard. This PR fixes the logic to filter out already pinned jobs and fill the pinboard up to the 500-job limit. It also ensures the pin count animation and max-size notifications trigger accurately. A new test suite has been added to verify these changes.

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PR created automatically by Jules for task 17814967778548766990 started by @moijes12

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