docs: update Now/INDEX for Phase 129-B join_k as-last

docs/development/current/main/phases/phase-129/PROGRESS.md

@@ -1,6 +1,6 @@
 # Phase 129 Progress Report
 
-## Status: P0-P3 Complete, P1 Requires User Decision
+## Status: P0/P2/P3 Complete, P1 in Progress (129-B complete)
 
 ### Completed Tasks ✅
 
@@ -37,7 +37,7 @@
 
 #### P1: Materialize join_k Continuation
 
-**Current State**: Analysis complete, awaiting user decision
+**Current State**: Phase 129-B (if-as-last) implemented; Phase 129-C (post-if) remains.
 
 **Key Findings**:
 1. Current `lower_if_node` is Phase 123-124 minimal (incomplete)
@@ -63,7 +63,7 @@
 - Pros: Incremental testing, clear rollback points
 - Cons: More commits (3), slightly slower
 
-**Decision Needed**: User/ChatGPT should choose Option A or B
+**Decision Needed**: None for 129-B; next is 129-C (post-if via post_k continuation).
 
 ## Test Results Summary