Introduce a complete approval system for document publishing. Document
versions can now require approval from selected reviewers before being
published, with automatic publishing once all approvers have approved.
- Add approval quorum and decision tables with backfill migration
- Implement request approval, approve, and reject flows with electronic
signature support for approve decisions
- Add employee approvals page with dedicated tab and pending approvals view
- Add changelog field to publish and request approval flows
- Pre-select previous version's approvers in the publish dialog
- Show quorum approvers in document list with 100 approver hard limit
- Expose approval workflow through GraphQL, MCP, and CLI
- Remove legacy default approvers feature entirely
- Add comprehensive e2e test coverage for approval workflows
Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>
