Fix learn 404, coin animation, full regions, and AI key errors.

Use numeric /learn/{num} routes, register Tailwind coin animations with方孔铜钱 UI, expand to 34 provinces, and surface missing OPENAI_API_KEY clearly.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/learn/gua-footer.tsx

@@ -1,12 +1,20 @@
 import Link from "next/link";
 import { Button } from "@/components/ui/button";
 import { Sparkles } from "lucide-react";
+import { guaNumFromMark } from "@/lib/content/zhouyi";
 
-export default function GuaFooter({ guaMark }: { guaMark: string }) {
+export default function GuaFooter({
+  guaMark,
+  guaNum,
+}: {
+  guaMark: string;
+  guaNum?: string;
+}) {
+  const num = guaNum ?? guaNumFromMark(guaMark);
   return (
     <div className="mt-8 flex flex-wrap gap-3 border-t pt-6">
       <Button asChild size="sm">
-        <Link href={`/liuyao?gua=${encodeURIComponent(guaMark)}`}>
+        <Link href={`/liuyao?gua=${num}`}>
           <Sparkles size={16} className="mr-1" />
           以此卦起卦
         </Link>

components/learn/markdown-content.tsx

@@ -24,9 +24,12 @@ function resolveLearnHref(
   if (href.endsWith("/index.md")) {
     const mark = href.replace(/\/index\.md$/, "").replace(/^\.\//, "");
     if (mark.startsWith("other/")) {
-      return `/learn/other/${mark.slice("other/".length)}`;
+      const folder = mark.slice("other/".length);
+      const num = folder.split(".")[0];
+      return `/learn/other/${num}`;
     }
-    return `${base}/${mark}`;
+    const num = mark.split(".")[0];
+    return `${base}/${num}`;
   }
   return href;
 }