docs: add privacy-safe screenshot checklist for Cross-Project Dashboard

[jmirchh75]

Description

Adds a privacy-safe screenshot checklist for Cross-Project Dashboard contributors, covering student identity, account details, enrolment information, tasks, marks, feedback, extensions, and browser details that must be removed or replaced with mock data before sharing screenshots in PRs, Teams messages, reports, portfolios, or handover documents.

Fixes # (issue)

Type of change

• This change requires a documentation update

How Has This Been Tested?

This is solely a documentation change - no functional testing required as no code was modified. The checklist was completed according to and reviewed against the ticket in the planner board.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have requested a review from @macite and @jakerenzella on the Pull Request