Add complete Calendar Elements Demo application

Built comprehensive demo app showcasing 24 calendar components:
- 4 Calendar Views (Month, Week, Day, Agenda)
- 4 Date/Time Pickers (Date, Time, Range, Duration)
- 8 Components (Event Card, Mini Calendar, Headers, Forms, etc.)
- 8 Widgets (Heatmap, Today, Badges, Indicators, etc.)

Features:
- Mist theme with animated gradient background and glassmorphism
- Apple theme with clean solid design
- Dark/light mode support
- Responsive design for all screen sizes
- Signal-based reactive state management
- Comprehensive mock data (13+ events, recurrence rules, time slots)
- Interactive navigation and event handling

Tech stack: Angular 19, TypeScript, SCSS, Luxon, RRule

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

tsconfig.app.json

@@ -0,0 +1,13 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./out-tsc/app",
+    "types": []
+  },
+  "files": [
+    "src/main.ts"
+  ],
+  "include": [
+    "src/**/*.d.ts"
+  ]
+}