refactor(pages,a11y,seo): enhance subpage metadata, semantic HTML, accessibility, and E2E regression tests

- Standardize Next.js Metadata and dynamic generateMetadata across all subpages
- Fix duplicate main landmark in publications page by replacing nested main with div
- Unify Members page spacing (space-y-10 sm:space-y-14, pt-6 md:pt-8) and responsive H2s
- Add aria-label and focus ring to CategoryNav View All links for a11y
- Derive dynamic course history semester ranges in Lectures page
- Add 3 comprehensive E2E test cases (test_08, test_09, test_10) for highlights, active border, CITE brand links, and English H1 headers

refer_landing_page/app/lectures/page.tsx

@@ -1,10 +1,19 @@
 import React from "react";
+import type { Metadata } from "next";
 import { semesters } from "../../content/lectures";
 
+export const metadata: Metadata = {
+  title: "Lectures",
+  description: "AI Agent Networking Lab (ANL) lecture courses and curriculum history",
+};
+
 export default function LecturesPage() {
   const recentSemesters = semesters.slice(0, 3);
   const olderSemesters = semesters.slice(3);
 
+  const oldestSem = olderSemesters[olderSemesters.length - 1];
+  const newestOlderSem = olderSemesters[0];
+
   return (
     <div className="container-content py-8 sm:py-12 space-y-10 sm:space-y-14">
       {/* Page Header */}
@@ -73,7 +82,7 @@ export default function LecturesPage() {
                 Browse all semesters
               </span>
               <p className="text-xs text-ink-mute font-mono">
-                Course history from 2016 Fall to 2024 Spring
+                Course history from {oldestSem ? `${oldestSem.year} ${oldestSem.term}` : "2004 Spring"} to {newestOlderSem ? `${newestOlderSem.year} ${newestOlderSem.term}` : "2024 Fall"} ({olderSemesters.length} Semesters)
               </p>
             </div>
             <span className="font-mono text-xs text-vermillion-dark font-bold border border-vermillion-dark px-3.5 py-1.5 rounded group-open:bg-vermillion-dark group-open:text-white dark:group-open:text-ivory transition-colors">