feat: replace static hardware fields with dynamic node properties

Replaces the 4 fixed hardware columns (cpu_count, cpu_model, ram_gb,
disk_gb) with a flexible properties system. Each property has a key,
value, icon (from a curated Lucide picker), and a visibility toggle
that controls whether it appears on the canvas node card.

- Backend: add `properties` JSON column to Node model; data migration
  converts existing hardware rows to properties with correct icons
  (idempotent, old columns kept for safety)
- Backend: add `properties` to NodeBase, NodeUpdate, NodeSave schemas
  and canvasSerializer so values survive canvas save/load
- Frontend: add NodeProperty type; new propertyIcons.ts registry (20
  icons); BaseNode renders visible properties with legacy hardware
  fallback for unmigrated nodes
- Frontend: DetailPanel gains interactive properties section (add /
  edit / remove / toggle visibility / icon picker) replacing the
  read-only hardware block; hardware section removed from NodeModal
- Tests: 6 migration tests, 7 API tests, 8 DetailPanel property tests,
  6 BaseNode render/fallback tests, 9 propertyIcons util tests

frontend/src/utils/__tests__/propertyIcons.test.ts

@@ -0,0 +1,53 @@
+import { describe, it, expect } from 'vitest'
+import { Cpu, HardDrive, MemoryStick } from 'lucide-react'
+import { PROPERTY_ICONS, PROPERTY_ICON_NAMES, resolvePropertyIcon } from '../propertyIcons'
+
+describe('PROPERTY_ICONS', () => {
+  it('contains the hardware migration icons', () => {
+    expect(PROPERTY_ICONS['Cpu']).toBe(Cpu)
+    expect(PROPERTY_ICONS['HardDrive']).toBe(HardDrive)
+    expect(PROPERTY_ICONS['MemoryStick']).toBe(MemoryStick)
+  })
+
+  it('has at least 10 icons', () => {
+    expect(Object.keys(PROPERTY_ICONS).length).toBeGreaterThanOrEqual(10)
+  })
+
+  it('every value is a renderable component (function or object)', () => {
+    for (const [, icon] of Object.entries(PROPERTY_ICONS)) {
+      // Lucide icons can be functions or forwardRef objects depending on environment
+      expect(icon).toBeTruthy()
+      expect(['function', 'object']).toContain(typeof icon)
+    }
+  })
+})
+
+describe('PROPERTY_ICON_NAMES', () => {
+  it('matches the keys of PROPERTY_ICONS', () => {
+    expect(PROPERTY_ICON_NAMES).toEqual(expect.arrayContaining(Object.keys(PROPERTY_ICONS)))
+    expect(PROPERTY_ICON_NAMES.length).toBe(Object.keys(PROPERTY_ICONS).length)
+  })
+})
+
+describe('resolvePropertyIcon', () => {
+  it('returns the icon for a known name', () => {
+    expect(resolvePropertyIcon('Cpu')).toBe(Cpu)
+    expect(resolvePropertyIcon('HardDrive')).toBe(HardDrive)
+  })
+
+  it('returns null for null input', () => {
+    expect(resolvePropertyIcon(null)).toBeNull()
+  })
+
+  it('returns null for undefined input', () => {
+    expect(resolvePropertyIcon(undefined)).toBeNull()
+  })
+
+  it('returns null for unknown icon name', () => {
+    expect(resolvePropertyIcon('NotARealIcon')).toBeNull()
+  })
+
+  it('returns null for empty string', () => {
+    expect(resolvePropertyIcon('')).toBeNull()
+  })
+})

frontend/src/utils/canvasSerializer.ts

@@ -28,6 +28,7 @@ export interface ApiNode extends Record<string, unknown> {
   ram_gb?: number | null
   disk_gb?: number | null
   show_hardware?: boolean
+  properties?: unknown[] | null
   width?: number | null
   height?: number | null
   bottom_handles?: number
@@ -100,6 +101,7 @@ export function serializeNode(n: Node<NodeData>): Record<string, unknown> {
     ram_gb: n.data.ram_gb ?? null,
     disk_gb: n.data.disk_gb ?? null,
     show_hardware: n.data.show_hardware ?? false,
+    properties: n.data.properties ?? [],
     width: n.width ?? null,
     height: n.height ?? null,
     bottom_handles: n.data.bottom_handles ?? 1,

frontend/src/utils/propertyIcons.ts

@@ -0,0 +1,53 @@
+import {
+  Battery,
+  Box,
+  Clock,
+  Cpu,
+  Database,
+  Globe,
+  HardDrive,
+  Hash,
+  Key,
+  Layers,
+  Link,
+  MemoryStick,
+  Monitor,
+  Network,
+  Server,
+  Shield,
+  Tag,
+  Thermometer,
+  Wifi,
+  Zap,
+} from 'lucide-react'
+import type { LucideIcon } from 'lucide-react'
+
+export const PROPERTY_ICONS: Record<string, LucideIcon> = {
+  Battery,
+  Box,
+  Clock,
+  Cpu,
+  Database,
+  Globe,
+  HardDrive,
+  Hash,
+  Key,
+  Layers,
+  Link,
+  MemoryStick,
+  Monitor,
+  Network,
+  Server,
+  Shield,
+  Tag,
+  Thermometer,
+  Wifi,
+  Zap,
+}
+
+export const PROPERTY_ICON_NAMES = Object.keys(PROPERTY_ICONS) as (keyof typeof PROPERTY_ICONS)[]
+
+export function resolvePropertyIcon(name: string | null | undefined): LucideIcon | null {
+  if (!name) return null
+  return PROPERTY_ICONS[name] ?? null
+}