fix: stabilize background operations and large embedding results

frontend/src/features/editor/linkNavigation.ts

@@ -0,0 +1,20 @@
+/** Editable anchors need explicit navigation; plain clicks keep editing the link. */
+export function installLinkNavigation(root: HTMLElement): () => void {
+  const navigate = (event: MouseEvent) => {
+    if (event.button !== 0 || !(event.ctrlKey || event.metaKey) || event.altKey) return
+    const target = event.target instanceof Element ? event.target : (event.target as Node | null)?.parentElement
+    const link = target?.closest<HTMLAnchorElement>('.ProseMirror a[href]')
+    if (!link || !root.contains(link)) return
+    const href = link.getAttribute('href')?.trim()
+    if (!href) return
+    // Consume modified clicks before Milkdown's link editor or native navigation.
+    event.preventDefault()
+    event.stopPropagation()
+    let url: URL
+    try { url = new URL(href, document.baseURI) } catch { return }
+    if (!['http:', 'https:', 'mailto:', 'tel:'].includes(url.protocol)) return
+    window.open(url.href, '_blank', 'noopener,noreferrer')
+  }
+  root.addEventListener('click', navigate, true)
+  return () => root.removeEventListener('click', navigate, true)
+}