debug(e2e): dump fresh fixture rstest.config.mts content on prepareFixtures

Temporary investigation. CI macos-14 e2e fails with mode B at every
aggregateTimeout value (100/500/3000), but identical local runs pass.
Suspecting that the cp() into the fresh sibling directory does not
include rstest.config.mts under some Actions runner condition, so the
child rstest falls back to the entry.ts default (5 ms). Print the
freshly copied config content so the CI log shows the actual file
seen by the child process.

Will be reverted.

Author: stormslowly

e2e/scripts/index.ts

@@ -312,6 +312,27 @@ export async function prepareFixtures({
     await fs.promises.symlink(distPath, exposedPath, 'dir');
   }
 
+  // RCA debug: dump rstest.config.mts content (if any) from the freshly
+  // copied fixture so CI logs show whether tools.rspack.aggregateTimeout
+  // actually reached the child rstest process. Will be reverted.
+  try {
+    const cfg = path.resolve(distPath, 'rstest.config.mts');
+    if (fs.existsSync(cfg)) {
+      const content = fs.readFileSync(cfg, 'utf-8');
+      process.stdout.write(
+        `__RCA_FIXTURE__ ${distPath}\n${content}__RCA_FIXTURE_END__\n`,
+      );
+    } else {
+      process.stdout.write(
+        `__RCA_FIXTURE__ ${distPath} (no rstest.config.mts)\n`,
+      );
+    }
+  } catch (e) {
+    process.stdout.write(
+      `__RCA_FIXTURE__ ${distPath} ERROR ${(e as Error).message}\n`,
+    );
+  }
+
   const update = (
     relativePath: string,
     content: string | ((raw: string) => string),