This PR implements comprehensive Microsoft OAuth authentication support for Firebase Authentication in the Auto Clicker AutoFill web extension, working alongside the existing Google OAuth implementation.

Key Changes

New Microsoft OAuth Package (@dhruv-techapps/shared-microsoft-oauth)

• Complete Microsoft OAuth implementation following the same patterns as Google OAuth
• Extension-compatible authentication flow using Chrome identity APIs and Microsoft OAuth 2.0
• Token management and user info retrieval from Microsoft Graph API
• Service layer for cross-context messaging between background and content scripts
• Comprehensive error handling with user-friendly error messages

Enhanced Firebase OAuth Integration

• Microsoft Firebase authentication using OAuthProvider with 'microsoft.com' provider ID
• Multi-provider support with new FirebaseMultiOauth2Background class supporting both Google and Microsoft
• Provider selection capability through FirebaseAuthProvider enum
• Unified authentication interface maintaining backward compatibility with existing Google OAuth usage

Usage Example

import { FirebaseMultiOauth2Background, FirebaseAuthProvider } from '@dhruv-techapps/shared-firebase-oauth';

// Initialize with both Google and Microsoft client IDs
const auth = getAuth(app);
const multiAuth = new FirebaseMultiOauth2Background(
  auth, 
  'google-client-id', 
  'microsoft-client-id'
);

// Sign in with Microsoft
await multiAuth.firebaseLogin(FirebaseAuthProvider.MICROSOFT);

// Or use provider-specific authentication
import { FirebaseMicrosoftOauth2Background } from '@dhruv-techapps/shared-firebase-oauth';
const microsoftAuth = new FirebaseMicrosoftOauth2Background(auth, 'microsoft-client-id');
await microsoftAuth.firebaseLogin();

Documentation and Examples

• Complete authentication documentation covering both Google and Microsoft providers
• Practical implementation examples for background scripts, content scripts, and UI integration
• Configuration guides for Azure app registration and Firebase setup
• Error handling patterns and best practices

Technical Implementation Details

• Uses Firebase's OAuthProvider with Microsoft's provider ID ('microsoft.com')
• Maintains same architecture patterns as existing Google OAuth implementation
• Supports Microsoft Graph API scopes for user profile access
• Compatible with Chrome extension identity APIs and manifest v3
• Provides both individual provider classes and unified multi-provider class

Backward Compatibility

All existing Google OAuth functionality remains unchanged. The new Microsoft OAuth support is additive and doesn't affect existing implementations.

Fixes #687.

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