feat: add Text node type to canvas

New canvas object Text with edit/create modal: text content (single
or multi-line), font (Inter, JetBrains Mono, Serif, System Sans),
size, color, border (style + width + color), background. Double-click
on node opens edit modal. Sidebar gets "Add Text" entry below "Add Zone".

Refs #124

frontend/src/components/canvas/nodes/TextNode.tsx

@@ -0,0 +1,73 @@
+import { NodeResizer, type NodeProps, type Node } from '@xyflow/react'
+import { useCanvasStore } from '@/stores/canvasStore'
+import type { NodeData } from '@/types'
+
+const FONT_FAMILIES: Record<string, string> = {
+  inter: 'Inter, sans-serif',
+  mono: '"JetBrains Mono", monospace',
+  serif: 'Georgia, serif',
+  sans: 'system-ui, sans-serif',
+}
+
+export function TextNode({ id, data, selected }: NodeProps<Node<NodeData>>) {
+  const setEditingTextId = useCanvasStore((s) => s.setEditingTextId)
+
+  const rc = data.custom_colors ?? {}
+  const borderColor = rc.border ?? '#30363d'
+  const borderStyle = rc.border_style ?? 'none'
+  const borderWidth = rc.border_width ?? 1
+  const backgroundColor = rc.background ?? 'transparent'
+  const textColor = rc.text_color ?? '#e6edf3'
+  const textSize: number = rc.text_size ?? 14
+  const fontFamily = FONT_FAMILIES[rc.font ?? 'inter'] ?? FONT_FAMILIES.inter
+
+  const content = data.text_content ?? data.label ?? ''
+
+  return (
+    <>
+      <NodeResizer
+        isVisible={selected}
+        minWidth={40}
+        minHeight={20}
+        handleStyle={{
+          width: 8,
+          height: 8,
+          borderRadius: 2,
+          background: '#00d4ff',
+          border: '1px solid #0d1117',
+        }}
+        lineStyle={{ borderColor: 'transparent' }}
+      />
+
+      <div
+        style={{
+          width: '100%',
+          height: '100%',
+          display: 'flex',
+          alignItems: 'center',
+          justifyContent: 'center',
+          padding: 8,
+          background: backgroundColor,
+          border: borderStyle === 'none' ? 'none' : `${borderWidth}px ${borderStyle} ${borderColor}`,
+          boxShadow: selected ? '0 0 0 1px #00d4ff, 0 0 8px #00d4ff44' : 'none',
+          borderRadius: 6,
+          boxSizing: 'border-box',
+          cursor: 'default',
+          color: textColor,
+          fontFamily,
+          fontSize: textSize,
+          fontWeight: 500,
+          userSelect: 'none',
+          whiteSpace: 'pre-wrap',
+          textAlign: 'center',
+        }}
+        onDoubleClick={(e) => {
+          e.stopPropagation()
+          setEditingTextId(id)
+        }}
+      >
+        {content}
+      </div>
+    </>
+  )
+}

frontend/src/components/canvas/nodes/__tests__/TextNode.test.tsx

@@ -0,0 +1,67 @@
+import { describe, it, expect, beforeEach } from 'vitest'
+import { render, fireEvent } from '@testing-library/react'
+import { ReactFlowProvider } from '@xyflow/react'
+import { TextNode } from '../TextNode'
+import { useCanvasStore } from '@/stores/canvasStore'
+import type { NodeData } from '@/types'
+import type { NodeProps, Node } from '@xyflow/react'
+
+function renderNode(data: Partial<NodeData> = {}) {
+  const fullData: NodeData = {
+    label: '',
+    type: 'text',
+    status: 'unknown',
+    services: [],
+    text_content: 'Hello',
+    ...data,
+  }
+  const props = {
+    id: 't1',
+    data: fullData,
+    selected: false,
+    type: 'text',
+    zIndex: 0,
+    isConnectable: true,
+    xPos: 0,
+    yPos: 0,
+    dragging: false,
+    deletable: true,
+    draggable: true,
+    selectable: true,
+    positionAbsoluteX: 0,
+    positionAbsoluteY: 0,
+    width: 200,
+    height: 60,
+    dragHandle: undefined,
+    parentId: undefined,
+    sourcePosition: undefined,
+    targetPosition: undefined,
+  } as unknown as NodeProps<Node<NodeData>>
+  return render(
+    <ReactFlowProvider>
+      <TextNode {...props} />
+    </ReactFlowProvider>
+  )
+}
+
+describe('TextNode', () => {
+  beforeEach(() => {
+    useCanvasStore.setState({ editingTextId: null })
+  })
+
+  it('renders text_content', () => {
+    const { getByText } = renderNode({ text_content: 'My label' })
+    expect(getByText('My label')).toBeDefined()
+  })
+
+  it('falls back to label when text_content is missing', () => {
+    const { getByText } = renderNode({ text_content: undefined, label: 'Fallback' })
+    expect(getByText('Fallback')).toBeDefined()
+  })
+
+  it('double-click sets editingTextId in store', () => {
+    const { getByText } = renderNode({ text_content: 'Edit me' })
+    fireEvent.doubleClick(getByText('Edit me'))
+    expect(useCanvasStore.getState().editingTextId).toBe('t1')
+  })
+})

frontend/src/components/canvas/nodes/nodeTypes.ts

@@ -2,6 +2,7 @@ import { IspNode, RouterNode, FirewallNode, SwitchNode, ServerNode, VmNode, LxcN
 import { ProxmoxGroupNode } from './ProxmoxGroupNode'
 import { GroupRectNode } from './GroupRectNode'
 import { GroupNode } from './GroupNode'
+import { TextNode } from './TextNode'
 
 export const nodeTypes = {
   isp: IspNode,
@@ -24,6 +25,7 @@ export const nodeTypes = {
   generic: GenericNode,
   groupRect: GroupRectNode,
   group: GroupNode,
+  text: TextNode,
   zigbee_coordinator: ZigbeeCoordinatorNode,
   zigbee_router: ZigbeeRouterNode,
   zigbee_enddevice: ZigbeeEndDeviceNode,