Reduce CI test output by using dots reporter

Add --reporter=dots to bun test invocations in the test runner script
to minimize output volume in CI. The dots reporter prints a single
character per test instead of full test names, significantly reducing
log size. When JUnit reporting is enabled, both reporters stack
correctly (dots to stdout, JUnit to file).

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

scripts/runner.node.mjs

@@ -1314,7 +1314,7 @@ async function spawnBunTest(execPath, testPath, opts = { cwd }) {
   const isReallyTest = isTestStrict(testPath) || absPath.includes("vendor");
   const args = opts["args"] ?? [];
 
-  const testArgs = ["test", ...args, `--timeout=${perTestTimeout}`];
+  const testArgs = ["test", ...args, `--timeout=${perTestTimeout}`, "--reporter=dots"];
 
   // This will be set if a JUnit file is generated
   let junitFilePath = null;