Add import/export, graph UX improvements, and contact management fixes.

Support vCard import and multi-format export, bulk delete with reliable local persistence, Ctrl+link relation creation, cluster-colored graph visualization, and right-click context menus for node details.

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

frontend/src/composables/useGraphNodeContextMenu.js

@@ -0,0 +1,48 @@
+import { ref } from 'vue'
+
+export function useGraphNodeContextMenu() {
+  const contextMenuOpen = ref(false)
+  const contextMenuNode = ref(null)
+  const contextMenuX = ref(0)
+  const contextMenuY = ref(0)
+
+  function openContextMenu(node, event) {
+    if (!node || !event) return
+    contextMenuNode.value = node
+    contextMenuX.value = event.clientX
+    contextMenuY.value = event.clientY
+    contextMenuOpen.value = true
+  }
+
+  function closeContextMenu() {
+    contextMenuOpen.value = false
+    contextMenuNode.value = null
+  }
+
+  function attachNodeContextHandlers(network, getNodes) {
+    const onContext = (params) => {
+      const domEvent = params.event?.srcEvent || params.event
+      domEvent?.preventDefault?.()
+      if (params.nodes?.length > 0) {
+        const id = params.nodes[0]
+        const node = getNodes().find((n) => String(n.id) === String(id))
+        if (node) openContextMenu(node, domEvent)
+        return
+      }
+      closeContextMenu()
+    }
+
+    network.on('oncontext', onContext)
+    return () => network.off('oncontext', onContext)
+  }
+
+  return {
+    contextMenuOpen,
+    contextMenuNode,
+    contextMenuX,
+    contextMenuY,
+    openContextMenu,
+    closeContextMenu,
+    attachNodeContextHandlers,
+  }
+}