Drops the now-unused snapshot_id/source_id columns from every table that carried them, the snapshots and controls_snapshots tables, the snapshots_type enum, and the snapshot-scoped indexes. Recreates the unique indexes that previously gated on snapshot_id IS NULL without the snapshot scope. The data was already cleaned up in the prior PR.

Summary by cubic

Drop the snapshot schema and scope across the DB, and update error handling to match the new unique index names. Removes all snapshot_id/source_id columns, deletes snapshot tables/enum, and recreates unique indexes without snapshot gating.

• Migration

  • Drop snapshot_id/source_id across affected tables; remove snapshot-scoped indexes (states_of_applicability_source_id_snapshot_id_uniq, states_of_applicability_name_organization_id_uniq, idx_findings_organization_snapshot, etc.); drop snapshots, controls_snapshots, and snapshots_type.
  • Recreate unique indexes without snapshot scope:
    • statements_of_applicability_name_organization_id_uniq
    • idx_findings_org_reference_id
    • processing_activity_dpias_processing_activity_id_uniq
    • processing_activity_tias_processing_activity_id_uniq

• Refactors

  • Update constraint-name checks in pkg/coredata/data_protection_impact_assessment.go and pkg/coredata/transfer_impact_assessment.go to the new unique index names.

^{Written for commit 89032df. Summary will update on new commits.}