The setup guides and test report pages currently don't link to each other, which can leave contributors uncertain about the next step after applying a patch or unsure how to apply a patch before writing a report.

Proposed changes

• get-setup-for-testing/test-core-tickets-with-grunt.md — Add a "Writing a Test Report" section linking to test-reports/patch-testing.
• get-setup-for-testing/test-core-tickets-with-playground.md — Add a "Writing a Test Report" section linking to test-reports/patch-testing.
• test-reports/patch-testing.md — Add a note linking back to the Playground and Grunt setup pages for contributors who haven't applied a patch yet.

This creates a two-way flow between setup and reporting, helping new contributors navigate the full testing workflow.