Implement gmail login, dashboard, and logout

[ann-aot]

Changes

Implemented Google login and logout functionality, including a dashboard view and route protection.

Notes

This PR integrates Google Identity Services for user authentication:

• Google Login: Users can log in via Google, with the prompt: 'select_account' configured to always show the account selection dialog.
• Authentication State: A new auth.ts store manages the authentication state (user info, tokens) and persists it to local storage.
• Protected Routes: Vue Router guards are implemented to protect routes, redirecting unauthenticated users to the /login page.
• Dashboard: A basic dashboard view (/dashboard) displays logged-in user information.
• Logout: A logout button is available in the application's top bar.
• Configuration: Requires VITE_GOOGLE_CLIENT_ID to be set in the .env file for the login to function.

Checklist

• Added meaningful title for pull request
• Unit tests pass
• E2E tests pass
• Linting checks pass

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