feat(network): add SVG export

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/network/DiagramHeader.tsx

@@ -1,6 +1,6 @@
 import { useState, useCallback, useRef, useEffect } from 'react'
 import { useNavigate } from 'react-router-dom'
-import { ChevronLeft, Save, Download, FileJson, Image, FileText, Undo2, Redo2, MousePointer2, Hand } from 'lucide-react'
+import { ChevronLeft, Save, Download, FileJson, FileCode, Image, FileText, Undo2, Redo2, MousePointer2, Hand } from 'lucide-react'
 import { cn } from '@/lib/utils'
 
 export type InteractionMode = 'select' | 'pan'
@@ -15,6 +15,7 @@ interface DiagramHeaderProps {
   onNameChange: (name: string) => void
   onSave: () => void
   onExportPng: () => void
+  onExportSvg: () => void
   onExportPdf: () => void
   onExportJson: () => void
   onUndo: () => void
@@ -35,6 +36,7 @@ export function DiagramHeader({
   onNameChange,
   onSave,
   onExportPng,
+  onExportSvg,
   onExportPdf,
   onExportJson,
   onUndo,
@@ -211,6 +213,12 @@ export function DiagramHeader({
             >
               <Image size={12} /> Export PNG
             </button>
+            <button
+              onClick={() => { onExportSvg(); setShowExportMenu(false) }}
+              className="flex w-full items-center gap-2 px-3 py-1.5 text-xs text-primary hover:bg-elevated"
+            >
+              <FileCode size={12} /> Export SVG
+            </button>
             <button
               onClick={() => { onExportPdf(); setShowExportMenu(false) }}
               className="flex w-full items-center gap-2 px-3 py-1.5 text-xs text-primary hover:bg-elevated"