docs(state): record phase 1 context session

.planning/STATE.md

@@ -1,3 +1,19 @@
+---
+gsd_state_version: 1.0
+milestone: v1.0
+milestone_name: milestone
+status: planning
+stopped_at: Phase 1 context gathered
+last_updated: "2026-03-10T16:14:54.320Z"
+last_activity: 2026-03-10 — Roadmap created, project initialized
+progress:
+  total_phases: 6
+  completed_phases: 0
+  total_plans: 0
+  completed_plans: 0
+  percent: 0
+---
+
 # Project State
 
 ## Project Reference
@@ -58,6 +74,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-10
-Stopped at: Roadmap created, ready to plan Phase 1
-Resume file: None
+Last session: 2026-03-10T16:14:54.317Z
+Stopped at: Phase 1 context gathered
+Resume file: .planning/phases/01-core-foundation/01-CONTEXT.md