feat(FN-3311): add version notes extractor for GitHub releases

Merges FN-3311 work into the release pipeline: adds a version notes extractor with tests and integrates GitHub release creation into the release script, plus a minor CSS design token consistency fix in the dashboard.

Fusion-Task-Id: FN-3311

scripts/lib/extract-version-notes.mjs

@@ -0,0 +1,32 @@
+/**
+ * Extract the changelog section for a specific version from the root CHANGELOG.md content.
+ * @param {string} content - Full CHANGELOG.md content (as formatted by syncRootChangelog)
+ * @param {string} version - Bare version string (e.g. "0.16.0"), NOT "v"-prefixed
+ * @returns {string} Release notes body, or a fallback like "Release v{version}" if not found
+ */
+export function extractVersionNotes(content, version) {
+  const fallback = `Release v${version}`;
+
+  if (!content || !version) {
+    return fallback;
+  }
+
+  const lines = content.split(/\r?\n/);
+  const header = `## ${version}`;
+  const startIndex = lines.findIndex((line) => line.trim() === header);
+
+  if (startIndex === -1) {
+    return fallback;
+  }
+
+  let endIndex = lines.length;
+  for (let i = startIndex + 1; i < lines.length; i += 1) {
+    if (lines[i].startsWith("## ")) {
+      endIndex = i;
+      break;
+    }
+  }
+
+  const body = lines.slice(startIndex + 1, endIndex).join("\n").trim();
+  return body || fallback;
+}