debug: log outputFolder + JSON files to docker logs; fix walker to use stat

- runner.js: console.log outputFolder, sitespeed INFO lines, and
  find output after test so everything appears in docker logs
- parser.js: switch walker from withFileTypes to stat (more reliable
  on Docker volumes); log every directory visited

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

parser.js

@@ -1,4 +1,4 @@
-import { readdir, readFile } from 'fs/promises';
+import { readdir, readFile, stat } from 'fs/promises';
 import { join } from 'path';
 
 /**
@@ -11,19 +11,22 @@ async function findPageSummaries(outputFolder) {
   const errors = [];
 
   async function walk(dir) {
-    let entries;
+    let names;
     try {
-      entries = await readdir(dir, { withFileTypes: true });
+      names = await readdir(dir);
     } catch (err) {
-      errors.push(`readdir failed on ${dir}: ${err.message}`);
+      errors.push(`readdir(${dir}): ${err.message}`);
       return;
     }
-    for (const e of entries) {
-      const full = join(dir, e.name);
-      if (e.isDirectory()) {
+    console.log(`[parser] walk ${dir} → [${names.join(', ')}]`);
+    for (const name of names) {
+      const full = join(dir, name);
+      let s;
+      try { s = await stat(full); } catch { continue; }
+      if (s.isDirectory()) {
         await walk(full);
-      } else if (e.name.endsWith('.pageSummary.json')) {
-        const plugin = e.name.replace('.pageSummary.json', '');
+      } else if (name.endsWith('.pageSummary.json')) {
+        const plugin = name.replace('.pageSummary.json', '');
         if (!summaries[plugin]) summaries[plugin] = [];
         summaries[plugin].push(full);
         console.log(`[parser] found: ${full}`);