Show segment rule changes (diff) in audit log detail view

### Is your feature request related to a problem?

When a segment is updated, the audit log detail view only shows the version number change. It does not display what actually changed in the segment rules (e.g. which trait conditions were added, removed, or modified).

This makes it difficult for teams to determine when and who added a specific value to a segment.

Use case: Customer needs to track when a specific build number was added to a segment rule, and by whom. Currently the only way to see this would be to compare version snapshots manually.

### Describe the solution you'd like.

The audit log detail for segment updates should show the diff of segment rules (previous vs new values), similar to how feature versioning history works for feature flags.

### Describe alternatives you've considered

Alternatives considered:
- Organisation audit log webhooks exist but provide the same metadata without rule level diffs
- The audit log API returns the same data as the UI with no additional segment change details

### Additional context

_No response_