Evaluate sync partition scoping

[JayVDZ]

Summary

Evaluate whether and how partition-scoped synchronisation could be supported. This was identified as a future enhancement during #72 (Phase 2).

Key Challenges

• ConnectedSystemObject (CSO) does not currently store which partition it was imported from — there is no PartitionId FK on the CSO model. A schema migration would be required to add this.
• Sync needs a holistic view of all CSOs to correctly resolve joins and avoid duplicate projections. Restricting sync to a single partition's CSOs could cause missed joins or incorrect projections if objects in other partitions are relevant.
• Need to determine whether partition-scoped sync has real-world value or whether the holistic approach is always correct.

Context

• Import partition scoping is already implemented and working (Confirm if a partition is needed/relevant for a Full Sync? #72 Phase 1)
• This is an evaluation task — the outcome may be "not needed" if holistic sync is always the correct approach