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, 6 insertions, 2 deletions

diff --git a/makima/src/bin/makima.rs b/makima/src/bin/makima.rs
index e5b1a5e..ac577b8 100644
--- a/makima/src/bin/makima.rs
+++ b/makima/src/bin/makima.rs
@@ -488,9 +488,13 @@ async fn run_supervisor(
         }
         SupervisorCommand::AdvancePhase(args) => {
             let client = ApiClient::new(args.common.api_url, args.common.api_key)?;
-            eprintln!("Advancing contract to phase: {}...", args.phase);
+            if args.confirmed {
+                eprintln!("Advancing contract to phase: {} (confirmed)...", args.phase);
+            } else {
+                eprintln!("Requesting phase advance to: {} (use --confirmed to proceed)...", args.phase);
+            }
             let result = client
-                .supervisor_advance_phase(args.common.contract_id, &args.phase)
+                .supervisor_advance_phase(args.common.contract_id, &args.phase, args.confirmed)
                 .await?;
             println!("{}", serde_json::to_string(&result.0)?);
         }