feat: document default project roles

Author: gregberge

docs/learn/team-members-and-roles.mdx

@@ -177,3 +177,19 @@ Adopting an observational role within the project scope, they ensure transparenc
 #### Key responsibilities
 
 - View and inspect all builds and screenshots
+
+## Default Project Roles
+
+When you set a default role in a specific project, all of your team’s contributors will automatically inherit that default role when they’re granted access to that project. This feature helps you streamline role management and maintain consistent permissions for new contributors.
+
+**To set a default role in a project:**
+
+1. Navigate to the project's **Settings** page.
+2. Scroll down to the **Access management** section.
+3. Click on **Set default contributor level**.
+4. Select the desired default role (Viewer, Reviewer, or Admin).
+5. Click **Save**.
+
+After setting this default, every team member with a role "contributor" will have access to this project with this default role. You can still override this by assigning a custom role to individual contributors later.
+
+This approach simplifies onboarding, helps ensure consistent access levels, and reduces the time spent manually configuring roles.