fix(frontend): clipboard polyfill for HTTP (non-secure) contexts — copy buttons threw writeText-of-undefined on nodes

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/main.ts

@@ -3,6 +3,26 @@ import { router } from './router'
 import App from './App.vue'
 import './style.css'
 
+// Clipboard polyfill: on nodes the app is served over plain HTTP (non-secure
+// context), where navigator.clipboard does not exist — every copy button would
+// throw "Cannot read properties of undefined (reading 'writeText')".
+if (!navigator.clipboard) {
+  Object.defineProperty(navigator, 'clipboard', {
+    value: {
+      async writeText(text: string) {
+        const ta = document.createElement('textarea')
+        ta.value = text
+        ta.style.cssText = 'position:fixed;opacity:0'
+        document.body.appendChild(ta)
+        ta.select()
+        document.execCommand('copy')
+        document.body.removeChild(ta)
+      },
+      async readText() { return '' },
+    },
+  })
+}
+
 const app = createApp(App)
 app.use(router)
 app.mount('#app')