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.

power.config.json

@@ -1,14 +1,16 @@
 {
-  "$schema": "https://aka.ms/power-apps/code/power.config.schema.json",
   "version": "1.0",
-  "app": {
-    "name": "outlook-lite",
-    "displayName": "Outlook Lite — Code Apps Demo",
-    "description": "Email client built with React + Fluent UI, powered by Power Platform connectors"
-  },
-  "dataSources": [],
+  "appId": "<your-app-id>",
+  "appDisplayName": "Outlook Lite",
+  "region": "prod",
+  "environmentId": "<your-environment-id>",
+  "description": "Email client built with React + Fluent UI, powered by Power Platform connectors",
+  "buildPath": "dist",
+  "buildEntryPoint": "index.html",
+  "localAppUrl": "http://localhost:5173",
+  "logoPath": "Default",
   "connectionReferences": {
-    "e9a483eb-1c10-473e-8d5c-a71f3f1f79a1": {
+    "<your-connection-reference-id>": {
       "id": "/providers/Microsoft.PowerApps/apis/shared_outlook",
       "displayName": "Outlook.com",
       "dataSources": [
@@ -16,5 +18,6 @@
       ],
       "dataSets": {}
     }
-  }
-}
+  },
+  "databaseReferences": {}
+}