feat(liveview): header View link opens active design as read-only canvas

Add an authenticated GET /api/v1/liveview/config endpoint exposing the
configured LIVEVIEW_KEY to logged-in admins, so the UI builds a
ready-to-use share link. The header View button opens
/view?key=...&design=<activeDesignId>; LiveView forwards ?design=<id>
to the public endpoint, which renders that design's canvas.

ha-relevant: maybe

frontend/src/App.tsx

@@ -31,7 +31,7 @@ import { useCanvasStore } from '@/stores/canvasStore'
 import { useDesignStore } from '@/stores/designStore'
 import { useAuthStore } from '@/stores/authStore'
 import { useThemeStore } from '@/stores/themeStore'
-import { canvasApi, designsApi } from '@/api/client'
+import { canvasApi, designsApi, liveviewApi } from '@/api/client'
 import { demoNodes, demoEdges } from '@/utils/demoData'
 import { useStatusPolling } from '@/hooks/useStatusPolling'
 import type { NodeData, EdgeData, CustomStyleDef } from '@/types'
@@ -457,6 +457,28 @@ export default function App() {
     }
   }, [nodes, edges, snapshotHistory, loadCanvas, markUnsaved])
 
+  // Open the read-only live view of the currently active design in a new tab.
+  // Standalone has no backend/key — it reads localStorage, so just open /view.
+  // Otherwise fetch the configured live view key and build /view?key=...&design=<id>.
+  const handleViewOnly = useCallback(async () => {
+    if (STANDALONE) {
+      window.open('/view', '_blank', 'noopener,noreferrer')
+      return
+    }
+    try {
+      const res = await liveviewApi.getConfig()
+      if (!res.data.enabled || !res.data.key) {
+        toast.error('Live view is disabled — set LIVEVIEW_KEY in the backend .env')
+        return
+      }
+      const params = new URLSearchParams({ key: res.data.key })
+      if (activeDesignId) params.set('design', activeDesignId)
+      window.open(`/view?${params.toString()}`, '_blank', 'noopener,noreferrer')
+    } catch {
+      toast.error('Failed to open live view')
+    }
+  }, [activeDesignId])
+
   const handleExport = useCallback(() => {
     const el = canvasRef.current?.querySelector<HTMLElement>('.react-flow')
     if (!el) { toast.error('Canvas not ready'); return }
@@ -601,6 +623,7 @@ export default function App() {
               onExportMd={handleExportMd}
               onExportYaml={handleExportYaml}
               onImportYaml={handleImportYaml}
+              onViewOnly={handleViewOnly}
             />
             <div className="flex flex-1 min-h-0">
               <div ref={canvasRef} className="flex-1 min-w-0 h-full">

frontend/src/api/__tests__/client.test.ts

@@ -158,6 +158,16 @@ describe('api/client', () => {
     expect(api.get).not.toHaveBeenCalled()
   })
 
+  it('liveviewApi.load forwards design as design_id when provided', () => {
+    mod.liveviewApi.load('k-1', 'design-9')
+    expect(publicApi.get).toHaveBeenCalledWith('/liveview', { params: { key: 'k-1', design_id: 'design-9' } })
+  })
+
+  it('liveviewApi.getConfig hits the authenticated config endpoint', () => {
+    mod.liveviewApi.getConfig()
+    expect(api.get).toHaveBeenCalledWith('/liveview/config')
+  })
+
   it('scanApi endpoints route correctly', () => {
     mod.scanApi.trigger()
     expect(api.post).toHaveBeenCalledWith('/scan/trigger')

frontend/src/api/client.ts

@@ -53,7 +53,9 @@ export const edgesApi = {
 }
 
 export const liveviewApi = {
-  load: (key: string) => publicApi.get('/liveview', { params: { key } }),
+  load: (key: string, design?: string) =>
+    publicApi.get('/liveview', { params: { key, ...(design ? { design_id: design } : {}) } }),
+  getConfig: () => api.get<{ enabled: boolean; key: string | null }>('/liveview/config'),
 }
 
 export const scanApi = {

frontend/src/components/LiveView.tsx

@@ -68,10 +68,14 @@ function LiveViewCanvas() {
     }
 
     // Already handled synchronously in useState initializer
-    const key = new URLSearchParams(window.location.search).get('key')
+    const search = new URLSearchParams(window.location.search)
+    const key = search.get('key')
     if (!key) return
+    // Optional ?design=<id> selects which canvas to render; backend falls back
+    // to the first design when omitted.
+    const design = search.get('design') ?? undefined
 
-    liveviewApi.load(key)
+    liveviewApi.load(key, design)
       .then((res) => {
         const { nodes: apiNodes, edges: apiEdges } = res.data
         const proxmoxMap = new Map<string, boolean>(

frontend/src/components/__tests__/LiveView.test.tsx

@@ -118,7 +118,15 @@ describe('LiveView (non-standalone)', () => {
     await waitFor(() => {
       expect(screen.getByTestId('react-flow')).toBeDefined()
     })
-    expect(liveviewApi.load).toHaveBeenCalledWith('correct-key')
+    expect(liveviewApi.load).toHaveBeenCalledWith('correct-key', undefined)
+  })
+
+  it('forwards ?design=<id> to the API so a specific canvas is loaded', async () => {
+    setSearch('?key=correct-key&design=elec-123')
+    vi.mocked(liveviewApi.load).mockResolvedValue(canvasPayload as never)
+    render(<LiveView />)
+    await waitFor(() => expect(screen.getByTestId('react-flow')).toBeDefined())
+    expect(liveviewApi.load).toHaveBeenCalledWith('correct-key', 'elec-123')
   })
 
   it('allows zooming out to 0.25 so large infra fits (matches the editor)', async () => {

frontend/src/components/panels/Toolbar.tsx

@@ -1,5 +1,5 @@
 import { useRef } from 'react'
-import { Save, LayoutDashboard, Download, Palette, Undo2, Redo2, HelpCircle, Table2, FileDown, Upload } from 'lucide-react'
+import { Save, LayoutDashboard, Download, Palette, Undo2, Redo2, HelpCircle, Table2, FileDown, Upload, Eye } from 'lucide-react'
 import { Button } from '@/components/ui/button'
 import { Logo } from '@/components/ui/Logo'
 import { useCanvasStore } from '@/stores/canvasStore'
@@ -15,9 +15,10 @@ interface ToolbarProps {
   onExportMd: () => void
   onExportYaml: () => void
   onImportYaml: (content: string) => void
+  onViewOnly: () => void
 }
 
-export function Toolbar({ onSave, onAutoLayout, onExport, onChangeStyle, onUndo, onRedo, onShortcuts, onExportMd, onExportYaml, onImportYaml }: ToolbarProps) {
+export function Toolbar({ onSave, onAutoLayout, onExport, onChangeStyle, onUndo, onRedo, onShortcuts, onExportMd, onExportYaml, onImportYaml, onViewOnly }: ToolbarProps) {
   const { hasUnsavedChanges, past, future } = useCanvasStore()
   const fileInputRef = useRef<HTMLInputElement>(null)
 
@@ -81,6 +82,9 @@ export function Toolbar({ onSave, onAutoLayout, onExport, onChangeStyle, onUndo,
       <Button size="sm" variant="ghost" className="gap-1.5 text-muted-foreground hover:text-foreground cursor-pointer hover:bg-[#21262d]" onClick={onExportMd} title="Copy inventory as Markdown table">
         <Table2 size={14} /> MD
       </Button>
+      <Button size="sm" variant="ghost" className="gap-1.5 text-muted-foreground hover:text-foreground cursor-pointer hover:bg-[#21262d]" onClick={onViewOnly} title="Open read-only live view of this canvas">
+        <Eye size={14} /> View
+      </Button>
       <Button size="sm" variant="ghost" className="gap-1.5 text-muted-foreground hover:text-foreground cursor-pointer hover:bg-[#21262d]" onClick={onShortcuts} title="Keyboard shortcuts (?)">
         <HelpCircle size={14} />
       </Button>