docs(05-tech-debt): create phase 5 plan — 4 plans across 2 waves

Wave 0 TDD stubs, Wave 1 parallel (registry + ReviewStep), Wave 2 act() fix.
Covers TECH-01 through TECH-05.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/STATE.md

@@ -1,11 +1,11 @@
 ---
 gsd_state_version: 1.0
 milestone: v1.1
-milestone_name: "Backlog & Tech Debt"
-status: roadmap_ready
-stopped_at: Roadmap created for v1.1 — 3 phases (5-7), 11 requirements mapped
-last_updated: "2026-03-27T00:00:00.000Z"
-last_activity: 2026-03-27 — v1.1 roadmap created, ready to plan Phase 5
+milestone_name: Backlog & Tech Debt
+status: planning
+stopped_at: Phase 5 context gathered
+last_updated: "2026-03-30T07:14:08.967Z"
+last_activity: 2026-03-27 — v1.1 roadmap created, 11 requirements mapped across 3 phases
 progress:
   total_phases: 3
   completed_phases: 0
@@ -74,6 +74,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-27T00:00:00.000Z
-Stopped at: v1.1 roadmap created — Phases 5-7 defined, all 11 requirements mapped
-Resume file: None
+Last session: 2026-03-30T07:14:08.962Z
+Stopped at: Phase 5 context gathered
+Resume file: .planning/phases/05-tech-debt/05-CONTEXT.md