refactor(core): dedupe shared config and runtime helpers

src/test-utils/chunk-test-helpers.ts

@@ -0,0 +1,22 @@
+export function countLines(text: string): number {
+  return text.split("\n").length;
+}
+
+export function hasBalancedFences(chunk: string): boolean {
+  let open: { markerChar: string; markerLen: number } | null = null;
+  for (const line of chunk.split("\n")) {
+    const match = line.match(/^( {0,3})(`{3,}|~{3,})(.*)$/);
+    if (!match) {
+      continue;
+    }
+    const marker = match[2];
+    if (!open) {
+      open = { markerChar: marker[0], markerLen: marker.length };
+      continue;
+    }
+    if (open.markerChar === marker[0] && marker.length >= open.markerLen) {
+      open = null;
+    }
+  }
+  return open === null;
+}