✅ Update progress for GamemasterExplorer refactoring and mark JsonViewer component as complete

docs/projects/Pokedex.Online/PROGRESS.md

@@ -123,7 +123,7 @@ Last Updated: January 28, 2026
 
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-## Phase 5: GamemasterExplorer Refactoring (6/9 complete)
+## Phase 5: GamemasterExplorer Refactoring (7/9 complete)
 **Duration**: 5-7 days  
 **Status**: In Progress  
 **Target**: Reduce from 1627 lines → ~400 lines (76% reduction)
@@ -184,13 +184,13 @@ Last Updated: January 28, 2026
 - [x] Auto-load last selected file
 - [x] Write component tests - 8 tests passing ✅
 
-### ⏳ Step 19: Create JsonViewer Component
-- [ ] Create `src/components/gamemaster/JsonViewer.vue`
-- [ ] Use `useGamemasterFiles` and `useLineSelection` composables
-- [ ] Implement syntax-highlighted JSON display
-- [ ] Add line numbers and click-to-select
-- [ ] Support virtual scrolling for large files
-- [ ] Write component tests
+### ✅ Step 19: Create JsonViewer Component
+- [x] Create `src/components/gamemaster/JsonViewer.vue`
+- [x] Use `useLineSelection` composable for selection state
+- [x] Implement syntax-highlighted JSON display
+- [x] Add line numbers and click-to-select
+- [x] Support virtual scrolling for large files
+- [x] Write component tests - 6 tests passing ✅
 
 ### ⏳ Step 20: Create FilterPanel Component
 - [ ] Create `src/components/gamemaster/FilterPanel.vue`