feat: add react-markdown dependency and update README with release process

scripts/check-changelog.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# * Verifies that CHANGELOG.md has an entry for the given version (e.g. 0.1.0 or v0.1.0).
+# * Use before tagging a release; can be wired into CI.
+# * Usage: ./scripts/check-changelog.sh <version>
+
+set -e
+
+VERSION="${1:-}"
+CHANGELOG="${CHANGELOG:-CHANGELOG.md}"
+
+if [ -z "$VERSION" ]; then
+  echo "Usage: $0 <version> (e.g. 0.1.0 or v0.1.0)" >&2
+  exit 1
+fi
+
+# Strip leading 'v' if present for consistent matching
+NORMALIZED="${VERSION#v}"
+
+if [ ! -f "$CHANGELOG" ]; then
+  echo "Error: $CHANGELOG not found (run from repo root)" >&2
+  exit 1
+fi
+
+# Keep a Changelog style: ## [1.0.0] or ## [1.0.0] - 2026-02-09
+if grep -qE "^## \[${NORMALIZED}\]" "$CHANGELOG"; then
+  echo "OK: CHANGELOG has an entry for version $NORMALIZED"
+  exit 0
+fi
+
+echo "Error: CHANGELOG.md has no entry for version $NORMALIZED (expected a line like '## [$NORMALIZED] - YYYY-MM-DD')" >&2
+exit 1