docs(state): record phase 5 context session

.planning/STATE.md

@@ -2,14 +2,16 @@
 gsd_state_version: 1.0
 milestone: v1.1
 milestone_name: Custom Sound Mappings
-status: Ready to plan
-stopped_at: Roadmap created for v1.1 (Phases 5-7)
-last_updated: "2026-03-26T15:30:00.000Z"
+status: planning
+stopped_at: Phase 5 context gathered
+last_updated: "2026-03-26T16:11:17.884Z"
+last_activity: 2026-03-26 — v1.1 roadmap created, Phases 5-7 defined
 progress:
   total_phases: 3
   completed_phases: 0
   total_plans: 0
   completed_plans: 0
+  percent: 0
 ---
 
 # Project State
@@ -33,6 +35,7 @@ Progress: [░░░░░░░░░░] 0%
 ## Performance Metrics
 
 **Velocity (v1.0 baseline):**
+
 - Total plans completed: 11
 - Average duration: 7.7 min
 - Total execution time: ~1.4 hours
@@ -66,6 +69,6 @@ None.
 
 ## Session Continuity
 
-Last session: 2026-03-26T15:30:00.000Z
-Stopped at: v1.1 roadmap written (ROADMAP.md, STATE.md, REQUIREMENTS.md traceability updated)
-Resume file: None
+Last session: 2026-03-26T16:11:17.877Z
+Stopped at: Phase 5 context gathered
+Resume file: .planning/phases/05-waveform-types-and-bank-decoupling/05-CONTEXT.md