🔐 Add LinkedIn Account Connection via Email & Password

Description

To enhance onboarding flexibility and remove friction, allow users to connect a LinkedIn account to ReactIn by entering their LinkedIn email and password directly within a secure flow. This feature is especially useful for agencies managing accounts without direct access to the client’s browser or extension.

ReactIn will use these credentials to perform a background login and initiate sync, removing the need for the Chrome Extension in certain cases and making the setup process faster and more scalable.