feat: Add enhanced analytics dashboard with advanced visualizations

- Created EnhancedInsightsDashboard with multiple chart types:
  - Area charts with gradients for activity trends
  - Radar chart for weekly activity patterns
  - 24-hour heatmap visualization
  - Bubble/scatter chart for correlations
  - Time of day distribution bar chart
- Added toggle between basic and enhanced chart views
- Implemented chart export functionality (PNG/PDF)
- Fixed API endpoint URLs (circadian-rhythm, query params)
- Fixed component library conflicts (shadcn/ui → MUI)
- Added comprehensive null safety for timestamp handling
- Added alert type translations in all 5 languages
- Installed html2canvas and jspdf for export features
- Applied consistent minimum width styling to all charts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

maternal-web/locales/zh/insights.json

@@ -69,5 +69,16 @@
     "both": "两者",
     "dry": "干",
     "unknown": "未知"
+  },
+  "alertTypes": {
+    "feeding_concern": "喂养问题",
+    "sleep_concern": "睡眠问题",
+    "diaper_concern": "尿布问题",
+    "growth_concern": "成长问题",
+    "health_concern": "健康问题",
+    "milestone_delay": "里程碑延迟",
+    "temperature_abnormal": "异常体温",
+    "dehydration_risk": "脱水风险",
+    "nutrition_concern": "营养问题"
   }
 }