Create deep link to add organizations

Goal:
Allow a user to open the app with a link.

Details:
- The link should open the app and land the user on the dashboard screen.
- If the app is not installed, the link should bring the user to the app in the app store.
- It will contain a JSON payload to customize the app for the organization
- JSON payload will be completed in another task.

Start with the repository README and identify the Android entry points responsible for opening the app and showing the dashboard. Implement the link behavior described in the issue, including the app-store fallback, while leaving the JSON payload for the separate task; done means the link opens the dashboard when the app is installed.

Written by the indexing model from the issue text.