[Alexandru Dima (alexdima)]

Adds the narrated overview video from #342907 to build/ripple/README.md, right after the introduction, as a quick way in before the details. In about 3½ minutes it covers the problem, how ripple works, how CI uses it, its safety nets and the expected impact. It is a bare github.com/user-attachments URL on its own line, which github.com renders as an inline player.

Notes for reviewers:

• The video shows ripple as of ci: run only the unit tests a change can affect on macOS and Windows #342907. Some details have changed since: ripple: drop the 50% limit and always run only the affected unit tests #344134 dropped the "more than half the work is affected" fallback, and ci: run only the integration tests a change can affect on macOS and Windows #344146 also selects integration tests.
• Docs only. The test planner entry of runEverything in vscode.jsonc excludes build/ripple/**/*.md, and the ripple cache key (Cargo.*, rust-toolchain.toml, src/**) is unchanged, so this should neither run every unit test nor rebuild ripple. Because the change is under build/ripple, the Ripple check runs instead of being skipped.

How to test

Open build/ripple/README.md on this branch on github.com and check that the video plays below the introduction.

Validation

• git show HEAD:build/ripple/README.md | jq -Rs '{text:., mode:"gfm", context:"microsoft/vscode"}' | gh api -X POST markdown --input - | grep -c '<video': passed, prints 1.
• gh api "repos/microsoft/vscode/contents/build/ripple/README.md?ref=agents/add-video-to-ripples-readme" -H "Accept: application/vnd.github.html" | grep -c '<video': passed, prints 1 (github.com's rendering of the file on this branch).
• npm run -s precommit (hygiene, run by the pre-commit hook): passed; it checked 0 files.
• Not run: compile and unit tests, since the change is Markdown only.

[Copilot]

🟢 Approval recommended

The small documentation-only addition matches the stated purpose and has no unresolved findings.

No open issues 🎉

What changed in this PR

Adds the existing ripple overview video below the README introduction, giving readers a quick introduction to the CI test-selection tool.

Changes:

• Adds a short introduction linking to the original PR, #342907.
• Includes the video attachment URL for inline playback on GitHub; no runtime or CI configuration changes.

No actionable issues were identified.

File	Description
build/​ripple/​README.md	Adds the overview video and its source PR link below the introduction.

_{Review effort: Balanced}