feat: Add contract management system improvements (Phase 1)makima/contract-management-improvements

- Add docs/contract-management-spec.md with full system design
- Add docs/plans/implementation-plan.md with 5-phase rollout plan
- Add validate_deliverable() function and use in mark_deliverable_complete
- Add PhaseChangeResult enum and change_contract_phase_with_version() with FOR UPDATE locking
- Enforce phase_guard at API level for all callers

This addresses critical issues in contract management:
- Deliverable validation to prevent marking non-existent deliverables complete
- Version conflict detection for phase changes with row locking
- Phase guard enforcement at API level (applies to all callers including supervisors)
- Comprehensive specification and implementation plan for future phases

1 files changed, 5 insertions, 0 deletions

diff --git a/makima/src/daemon/cli/supervisor.rs b/makima/src/daemon/cli/supervisor.rs
index 9ad7aef..cb84ffa 100644
--- a/makima/src/daemon/cli/supervisor.rs
+++ b/makima/src/daemon/cli/supervisor.rs
@@ -218,6 +218,11 @@ pub struct AdvancePhaseArgs {
     /// The phase to advance to (specify, plan, execute, review)
     #[arg(index = 1)]
     pub phase: String,
+
+    /// Confirm the phase transition (required when phase_guard is enabled).
+    /// Without this flag, the command will return deliverables for review.
+    #[arg(long, short = 'y')]
+    pub confirmed: bool,
 }
 
 /// Arguments for mark-deliverable command.