fix: address Copilot review on rename commit ad14943

- src/pages/{en,ja}/cookbook/[...slug].astro: pass lang prop to
  SidebarTocHeadings. The earlier Copilot fix (commit 5a9186c) wired
  lang through the cli/themes/vfm/viewer slug pages but missed the
  new-features slug page (now cookbook). Without lang, the toggle
  aria-label rendered as "Toggle subsections of <heading>" even on
  Japanese pages.

- src/layouts/DocsLayout.astro: align global-nav Tutorials/FAQ URLs
  with the home sidebar. Both now use https://vivliostyle.org/en/...
  and https://vivliostyle.org/ja/... — the global nav was previously
  using the bare /tutorials/ and /faq/ paths for en pages, which
  required the marketing site to redirect.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ogwata

src/layouts/DocsLayout.astro

@@ -48,7 +48,7 @@ const navLinks = {
   ],
   tutorial: {
     label: navLabels.tutorial,
-    href: isJa ? 'https://vivliostyle.org/ja/tutorials/' : 'https://vivliostyle.org/tutorials/',
+    href: isJa ? 'https://vivliostyle.org/ja/tutorials/' : 'https://vivliostyle.org/en/tutorials/',
     external: true,
   },
   cookbook: {
@@ -70,7 +70,7 @@ const navLinks = {
   },
   faq: {
     label: navLabels.faq,
-    href: isJa ? 'https://vivliostyle.org/ja/faq/' : 'https://vivliostyle.org/faq/',
+    href: isJa ? 'https://vivliostyle.org/ja/faq/' : 'https://vivliostyle.org/en/faq/',
     external: true,
   },
 };

src/pages/en/cookbook/[...slug].astro

@@ -75,7 +75,7 @@ const nextPage = currentIndex < sortedDocs.length - 1 ? sortedDocs[currentIndex
             <a href={itemPath} aria-current={isActive ? 'page' : undefined}>
               {item.data.title || item.id}
             </a>
-            {isActive && <SidebarTocHeadings headings={headings} />}
+            {isActive && <SidebarTocHeadings headings={headings} lang="en" />}
           </li>
         );
       })}

src/pages/ja/cookbook/[...slug].astro

@@ -73,7 +73,7 @@ const nextPage = currentIndex < sortedDocs.length - 1 ? sortedDocs[currentIndex
             <a href={itemPath} aria-current={isActive ? 'page' : undefined}>
               {item.data.title || item.id}
             </a>
-            {isActive && <SidebarTocHeadings headings={headings} />}
+            {isActive && <SidebarTocHeadings headings={headings} lang="ja" />}
           </li>
         );
       })}