fix(dashboard): resolve widget sizing and detection issues

Issue 1: PresentCharacters widget too small with gaps
- Increase height from h:3 to h:4 in defaultLayout.js
- Widget's defaultSize is h:2 but layout had h:3, creating mismatch
- Now properly fills vertical space without gaps

Issue 2: Recent Events not appearing in reset/auto-arrange
Root cause: previousTrackerConfig starts as null, preventing widget detection

Fixes:
- Initialize previousTrackerConfig on dashboard load (dashboardIntegration.js)
  - Deep clone trackerConfig after dashboard init
  - Enables detectConfigChanges() to work on first load
- Reset previousTrackerConfig to null in resetLayout() (dashboardManager.js)
  - Ensures fresh detection after layout reset
  - Prevents stale comparison data

Verified: Recent Events enabled by default in tracker config (state.js:95)

Result:
✅ PresentCharacters fills space properly
✅ Recent Events appears in reset layout
✅ Recent Events appears in auto-arrange
✅ Tracker editor enable/disable now works correctly

src/systems/dashboard/dashboardManager.js

@@ -1439,6 +1439,11 @@ export class DashboardManager {
         console.log('[DashboardManager] Regenerating fresh default layout...');
         this.defaultLayout = generateDefaultDashboard();
 
+        // Reset previousTrackerConfig for fresh widget detection
+        // This ensures the comparison logic works correctly after reset
+        this.previousTrackerConfig = null;
+        console.log('[DashboardManager] Reset previousTrackerConfig for fresh widget detection');
+
         if (!this.defaultLayout) {
             console.warn('[DashboardManager] Failed to generate default layout');
             return;