docs(16-02): complete consolidated HTML export plan

- SUMMARY.md: BuildConsolidatedHtml with expandable location sub-lists, by-site view suppression, ViewModel wiring
- STATE.md: updated position, decisions, session
- ROADMAP.md: phase 16 marked Complete (2/2 plans with summaries)

.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 16-01-PLAN.md
-last_updated: "2026-04-09T10:34:56.209Z"
+stopped_at: Completed 16-02-PLAN.md
+last_updated: "2026-04-09T10:39:46.925Z"
 last_activity: 2026-04-09 — Roadmap created for v2.3 (phases 15-19)
 progress:
   total_phases: 5
-  completed_phases: 1
+  completed_phases: 2
   total_plans: 4
-  completed_plans: 3
+  completed_plans: 4
 ---
 
 # Project State
@@ -66,6 +66,8 @@ Decisions are logged in PROJECT.md Key Decisions table.
 - [Phase 15-consolidation-data-model]: RPT-04-g test data uses 11 rows (not 10) to produce 7 consolidated rows — plan description had a counting error; 4 unique rows + 3 merged groups = 7
 - [Phase 16-01]: Consolidated branch uses early-return pattern inside WriteSingleFileAsync to leave existing code path untouched
 - [Phase 16-01]: PermissionsViewModel gets MergePermissions as no-op placeholder reserved for future use
+- [Phase 16-report-consolidation-toggle]: BuildConsolidatedHtml is a private method via early-return in BuildHtml — existing code path completely untouched
+- [Phase 16-report-consolidation-toggle]: Separate locIdx counter for location groups (loc0, loc1...) distinct from grpIdx for user groups (ugrp0...) prevents ID collision
 
 ### Pending Todos
 
@@ -77,7 +79,7 @@ None.
 
 ## Session Continuity
 
-Last session: 2026-04-09T10:34:56.207Z
-Stopped at: Completed 16-01-PLAN.md
+Last session: 2026-04-09T10:39:46.923Z
+Stopped at: Completed 16-02-PLAN.md
 Resume file: None
 Next step: `/gsd:plan-phase 15`