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.

.gitignore

@@ -0,0 +1,21 @@
+# dependencies
+node_modules/
+
+# build output
+dist/
+
+# auto-generated Power Platform schemas (contain environment-specific URLs)
+.power/
+
+# editor
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# env
+.env
+.env.*