chore: seal Design Vision v1 and monorepo scaffold

Archive the differentiated YuXinGu product docs, AI engineering system,
design contract, and Go/Vue scaffold. Next execution prioritizes Cece-parity
over early innovation (see .ai/product/STRATEGY.md).

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

js/home.js

@@ -0,0 +1,14 @@
+function goDecode(){
+  var y=document.getElementById('dy').value.trim();
+  var m=document.getElementById('dm').value.trim();
+  var d=document.getElementById('dd').value.trim();
+  if(!y||!m||!d){alert('请输入完整的出生年月日');return;}
+  location.href='pages/decode.html?y='+encodeURIComponent(y)+'&m='+encodeURIComponent(m)+'&d='+encodeURIComponent(d);
+}
+['dy','dm','dd'].forEach(function(id){
+  var el=document.getElementById(id);
+  if(!el) return;
+  el.addEventListener('keydown',function(e){
+    if(e.key==='Enter')goDecode();
+  });
+});