Replace the per-approver add/remove model with a quorum-based approval
system. Documents now have default approvers that are pre-populated when
requesting approval, and the publish dialog lets users adjust the list
before submitting.
Key changes:
- Add PENDING_APPROVAL document version status with dedicated transitions
- Introduce approval quorums with request/approve/reject/void lifecycle
- Add default approvers per document (stored in document_default_approvers)
with MERGE-based upsert for efficient sync
- Add NoDuplicates validator for slice fields
- Split ALTER TYPE ADD VALUE migrations into separate files (required by
PostgreSQL when run inside transactions)
- Use VOIDED consistently for both quorum status and decision state enums
- Expose void/approve/reject through GraphQL and MCP, with e2e tests
- Add approval management UI: publish dialog with approver selection,
approval list with void support, and external approve/reject page
Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>