feat(web): move feedback entry from floating button to about section (#112)

Replace the fixed bottom-right ember-500 floating button with a
dedicated fourth column in the about grid, matching existing visual
language (smallcaps heading + icon link). Adds submitFeedback and
feedbackDescription i18n keys for zh-CN, en, ja.

Grid uses md:grid-cols-2 lg:grid-cols-4 for better mid-screen
responsiveness.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

app/[locale]/page.tsx

@@ -2077,7 +2077,7 @@ export default function HomePage() {
           </p>
         </div>
 
-        <div className="mx-auto grid max-w-4xl grid-cols-1 gap-y-10 text-center md:grid-cols-3 md:gap-x-10">
+        <div className="mx-auto grid max-w-5xl grid-cols-1 gap-y-10 text-center md:grid-cols-2 lg:grid-cols-4 md:gap-x-10">
           <div>
             <p className="text-[10px] smallcaps text-clay-500 mb-3">{t("home.about.team")}</p>
             <p className="font-serif italic text-clay-700 text-base leading-relaxed">
@@ -2134,6 +2134,22 @@ export default function HomePage() {
               <span className="font-sans text-sm text-clay-900">575404333</span>
             </p>
           </div>
+
+          <div>
+            <p className="text-[10px] smallcaps text-clay-500 mb-3">{t("home.ui.feedback")}</p>
+            <p className="font-serif text-clay-700 text-base leading-relaxed mb-4">
+              {t("home.about.feedbackDescription")}
+            </p>
+            <a
+              href="https://tally.so/r/VLqO1M"
+              target="_blank"
+              rel="noopener noreferrer"
+              className="inline-flex items-center gap-2 text-clay-700 hover:text-ember-500 transition-colors"
+            >
+              <i className="fa-solid fa-comment-dots text-[15px]" />
+              <span className="font-sans text-sm">{t("home.ui.submitFeedback")}</span>
+            </a>
+          </div>
         </div>
 
         <div className="hairline-full w-full mt-14 md:mt-20 mb-12 md:mb-16" />
@@ -2155,17 +2171,6 @@ export default function HomePage() {
         </div>
       </footer>
 
-      {/* ================== 反馈悬浮按钮 ================== */}
-      <a
-        href="https://tally.so/r/VLqO1M"
-        target="_blank"
-        rel="noopener noreferrer"
-        aria-label={t("home.ui.feedback")}
-        className="fixed right-5 bottom-[calc(1.25rem+env(safe-area-inset-bottom))] z-50 flex items-center gap-2 rounded-full bg-ember-500 pl-3.5 pr-4 py-2.5 text-sm text-cream-50 shadow-lg transition-all hover:bg-clay-800 active:scale-95"
-      >
-        <i className="fa-solid fa-comment-dots text-[13px]" />
-        <span className="font-sans tracking-wide">{t("home.ui.feedback")}</span>
-      </a>
 
       {styleOpen && styleRow >= 0 && (
         <StyleModal