docs: add placeholder for the standing CI validation PR

This file has no functional purpose; it exists so this branch has a
trivial diff to keep a PR open against main. Real changes land on main
directly for faster feedback; this PR gets rebased after each push so
pull_request-triggered checks (and anything chained off them via
workflow_run) can still be observed running on a live PR.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: indradhanush

.github/CI_VALIDATION_PR.md

@@ -0,0 +1,11 @@
+# CI validation PR
+
+This branch exists only to keep a PR open against `main` so that
+`pull_request`-triggered checks (CI, and anything chained off it via
+`workflow_run`) can be observed running for real.
+
+Workflow:
+- Real changes land on `main` directly (fast feedback, no PR round-trip).
+- After each push to `main`, this branch gets rebased onto the new tip and
+  force-pushed, keeping this PR's diff to just this file.
+- Do not merge this PR.