Add laptop and mobile node types

Personal computing devices (laptops, phones, tablets) currently collapse
into the generic icon because the type vocabulary has no entries for
them. This adds two new NodeTypes with Lucide icons:

- laptop  -> Laptop icon (reuses the computer accent color per theme)
- mobile  -> Smartphone icon (new pink accent #ec4899 across themes)

Touches:
- types/index.ts                    NodeType union + NODE_TYPE_LABELS
- utils/nodeIcons.ts                Lucide import + ICON_REGISTRY +
                                    NODE_TYPE_DEFAULT_ICONS
- utils/themes.ts                   nodeAccents in all 6 themes
- canvas/nodes/index.tsx            LaptopNode + MobileNode wrappers
- canvas/nodes/nodeTypes.ts         register in react-flow nodeTypes
- modals/NodeModal.tsx              new "Personal" type group
- modals/CustomStyleModal.tsx       expose new types in style editor
- types/__tests__/types.test.ts     enumerate new types
- utils/__tests__/themes.test.ts    enumerate new types

Backwards-compatible: existing nodes typed as 'generic', 'server', etc.
keep rendering exactly as before. No data migration required.

frontend/src/utils/nodeIcons.ts

@@ -24,7 +24,7 @@ import {
   // Communications
   Mail, MessageSquare, Phone,
   // Misc devices
-  Printer, Smartphone, Search, Filter, BookOpen, PlugZap, Type,
+  Printer, Smartphone, Laptop, Search, Filter, BookOpen, PlugZap, Type,
 } from 'lucide-react'
 import type { LucideIcon } from 'lucide-react'
 
@@ -50,6 +50,7 @@ export const ICON_REGISTRY: IconEntry[] = [
   { key: 'wifi',       label: 'Access Point',         category: 'Infrastructure', icon: Wifi },
   { key: 'circle',     label: 'Generic',              category: 'Infrastructure', icon: Circle },
   { key: 'monitor',    label: 'Workstation',          category: 'Infrastructure', icon: Monitor },
+  { key: 'laptop',     label: 'Laptop',               category: 'Infrastructure', icon: Laptop },
   { key: 'smartphone', label: 'Phone / Mobile',       category: 'Infrastructure', icon: Smartphone },
   { key: 'printer',    label: 'Printer',              category: 'Infrastructure', icon: Printer },
   { key: 'plugzap',    label: 'CPL / Powerline',      category: 'Infrastructure', icon: PlugZap },
@@ -167,6 +168,8 @@ export const NODE_TYPE_DEFAULT_ICONS: Record<NodeType, LucideIcon> = {
   camera:       Cctv,
   printer:      Printer,
   computer:     Monitor,
+  laptop:       Laptop,
+  mobile:       Smartphone,
   cpl:          PlugZap,
   docker_host:       Anchor,
   docker_container:  Package,