docs(19-01): complete AppRegistrationService plan execution

- 19-01-SUMMARY.md: service layer implementation with rollback pattern
- STATE.md: progress 98%, decisions added, session updated
- ROADMAP.md: phase 19 in-progress (1/2 plans)
- REQUIREMENTS.md: APPREG-02, APPREG-03, APPREG-06 marked complete

.planning/STATE.md

@@ -3,14 +3,14 @@ gsd_state_version: 1.0
 milestone: v2.3
 milestone_name: Tenant Management & Report Enhancements
 status: planning
-stopped_at: Completed 18-02-PLAN.md
-last_updated: "2026-04-09T12:37:02.452Z"
+stopped_at: Completed 19-01-PLAN.md
+last_updated: "2026-04-09T13:15:04.040Z"
 last_activity: 2026-04-09 — Roadmap created for v2.3 (phases 15-19)
 progress:
   total_phases: 5
   completed_phases: 4
-  total_plans: 8
-  completed_plans: 8
+  total_plans: 10
+  completed_plans: 9
 ---
 
 # Project State
@@ -76,6 +76,9 @@ Decisions are logged in PROJECT.md Key Decisions table.
 - [Phase 18-auto-take-ownership]: AutoTakeOwnership ViewModel setter uses fire-and-forget pattern matching DataFolder
 - [Phase 18-auto-take-ownership]: Toggle read before scan loop (not in exception filter) — await in when clause unsupported; pre-read bool preserves semantics
 - [Phase 18-auto-take-ownership]: WasAutoElevated DataTrigger last in RowStyle.Triggers — amber wins over RiskLevel color
+- [Phase 19-app-registration-removal]: AppRegistrationService uses AppGraphClientFactory alias to disambiguate from Microsoft.Graph.GraphClientFactory
+- [Phase 19-app-registration-removal]: BuildRequiredResourceAccess declared internal to enable direct unit testing without live Graph calls
+- [Phase 19-app-registration-removal]: SharePoint AllSites.FullControl GUID marked LOW confidence — must be verified against live tenant
 
 ### Pending Todos
 
@@ -87,7 +90,7 @@ None.
 
 ## Session Continuity
 
-Last session: 2026-04-09T12:34:21.588Z
-Stopped at: Completed 18-02-PLAN.md
+Last session: 2026-04-09T13:15:04.038Z
+Stopped at: Completed 19-01-PLAN.md
 Resume file: None
 Next step: `/gsd:plan-phase 15`