docs(38-01): complete admin tag backend plan

- Add 38-01-SUMMARY.md (schema+service+routes+tests)
- Advance plan counter to 2/2, progress to 97%
- Mark 38-01 complete in ROADMAP.md

.planning/STATE.md

@@ -3,15 +3,15 @@ gsd_state_version: 1.0
 milestone: v2.4
 milestone_name: Admin Foundation
 status: executing
-stopped_at: Phase 38 context gathered
-last_updated: "2026-04-19T19:30:00.000Z"
-last_activity: 2026-04-19 -- Phase 38 context gathered (tag management, hierarchy decisions)
+stopped_at: Completed 35-03-PLAN.md — FIX-05 (cursor-pointer audit) resolved
+last_updated: "2026-04-19T20:29:07.741Z"
+last_activity: 2026-04-19
 progress:
   total_phases: 20
-  completed_phases: 8
-  total_plans: 34
-  completed_plans: 32
-  percent: 94
+  completed_phases: 10
+  total_plans: 38
+  completed_plans: 37
+  percent: 97
 ---
 
 # Project State
@@ -26,9 +26,9 @@ See: .planning/PROJECT.md (updated 2026-04-19)
 ## Current Position
 
 Phase: 36 (Admin Role & Panel Foundation) — EXECUTING
-Plan: 1 of 2
-Status: Executing Phase 36
-Last activity: 2026-04-19 -- Phase 36 execution started
+Plan: 2 of 2
+Status: Ready to execute
+Last activity: 2026-04-19
 
 Progress: [████████░░] 94%
 
@@ -110,6 +110,6 @@ Items carried forward from v2.3:
 
 ## Session Continuity
 
-Last session: 2026-04-19T17:52:29.341Z
+Last session: 2026-04-19T20:29:07.738Z
 Stopped at: Completed 35-03-PLAN.md — FIX-05 (cursor-pointer audit) resolved
 Resume file: None