feat: integrate Microsoft Power Apps SDK and enhance email handling

- Added dependency for @microsoft/power-apps to package.json.
- Updated power.config.json to include appId, environmentId, and connection references.
- Implemented sanitisation function for HTML content in App.tsx to prevent XSS.
- Enhanced error handling in email loading and marking as read functionalities.
- Updated email display logic to handle HTML content and previews.
- Refactored OutlookService to use auto-generated service from @microsoft/power-apps.
- Added new methods for sending, marking as read, and deleting emails in OutlookService.
- Updated types for Email to include bodyPreview, isHtml, hasAttachments, and importance.
- Configured Vite to exclude @microsoft/power-apps/data from the build.
- Created .gitignore to exclude build artifacts and environment files.
- Added local development shim for @microsoft/power-apps/data to support local testing.
- Defined type stubs for @microsoft/power-apps/data to facilitate local development.

package.json

@@ -11,6 +11,7 @@
   "dependencies": {
     "@fluentui/react-components": "^9.73.0",
     "@fluentui/react-icons": "^2.0.324",
+    "@microsoft/power-apps": "^1.1.1",
     "react": "^19.0.0",
     "react-dom": "^19.0.0"
   },