feat: add Docker node type, group rect border style, and categorized node type selector

- Fix DockerNode default icon: use Anchor instead of Package
- Add border_style option to Group Rectangle (solid/dashed/dotted/double/none)
- Group node type selector by category (Hardware, Virtualization, IoT, Generic)
- Add tests for border style feature

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

@@ -28,6 +28,7 @@ describe('ICON_REGISTRY', () => {
     expect(keys).toContain('play')      // Jellyfin
     expect(keys).toContain('shield')    // Pi-hole
     expect(keys).toContain('anchor')    // Portainer
+    expect(keys).toContain('package')   // Docker Host
     expect(keys).toContain('key')       // Vaultwarden
     expect(keys).toContain('database')  // DB services
     expect(keys).toContain('cctv')      // IP Camera / CCTV

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

@@ -4,7 +4,7 @@ import type { NodeType, EdgeType, NodeStatus } from '@/types'
 
 const NODE_TYPES: NodeType[] = [
   'isp', 'router', 'switch', 'server', 'proxmox', 'vm', 'lxc',
-  'nas', 'iot', 'ap', 'camera', 'printer', 'computer', 'cpl', 'generic', 'groupRect',
+  'nas', 'iot', 'ap', 'camera', 'printer', 'computer', 'cpl', 'docker', 'generic', 'groupRect',
 ]
 const EDGE_TYPES: EdgeType[] = ['ethernet', 'wifi', 'iot', 'vlan', 'virtual', 'cluster']
 const STATUS_TYPES: NodeStatus[] = ['online', 'offline', 'pending', 'unknown']
@@ -84,6 +84,7 @@ describe('THEMES', () => {
     expect(d.nodeAccents.server.border).toBe('#a855f7')
     expect(d.nodeAccents.isp.border).toBe('#00d4ff')
     expect(d.nodeAccents.proxmox.border).toBe('#ff6e00')
+    expect(d.nodeAccents.docker.border).toBe('#2496ED')
     expect(d.nodeCardBackground).toBe('#21262d')
     expect(d.nodeIconBackground).toBe('#161b22')
     expect(d.canvasBackground).toBe('#0d1117')

frontend/src/utils/nodeIcons.ts

@@ -14,7 +14,7 @@ import {
   // Transfers & sync
   Download, Upload, RefreshCw,
   // Containers & Dev
-  Anchor, GitBranch, Terminal, Code2, Settings,
+  Anchor, Package, GitBranch, Terminal, Code2, Settings,
   // Communications
   Mail, MessageSquare, Phone,
   // Misc devices
@@ -98,6 +98,7 @@ export const ICON_REGISTRY: IconEntry[] = [
 
   // --- Containers & Dev ---
   { key: 'anchor',    label: 'Portainer / Docker',   category: 'Dev & Containers', icon: Anchor },
+  { key: 'package',   label: 'Docker Host',          category: 'Dev & Containers', icon: Package },
   { key: 'gitbranch', label: 'Gitea / Gitlab',       category: 'Dev & Containers', icon: GitBranch },
   { key: 'terminal',  label: 'SSH / Shell',          category: 'Dev & Containers', icon: Terminal },
   { key: 'code',      label: 'VS Code Server',       category: 'Dev & Containers', icon: Code2 },

frontend/src/utils/themes.ts

@@ -56,6 +56,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:  { border: '#8b949e', icon: '#8b949e' },
         computer: { border: '#a855f7', icon: '#a855f7' },
         cpl:      { border: '#e3b341', icon: '#e3b341' },
+        docker:   { border: '#2496ED', icon: '#2496ED' },
         generic:  { border: '#8b949e', icon: '#8b949e' },
         groupRect:{ border: '#00d4ff', icon: '#00d4ff' },
       },
@@ -109,6 +110,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:  { border: '#94a3b8', icon: '#94a3b8' },
         computer: { border: '#c084fc', icon: '#c084fc' },
         cpl:      { border: '#fbbf24', icon: '#fbbf24' },
+        docker:   { border: '#2496ED', icon: '#2496ED' },
         generic:  { border: '#94a3b8', icon: '#94a3b8' },
         groupRect:{ border: '#22d3ee', icon: '#22d3ee' },
       },
@@ -162,6 +164,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:  { border: '#6b7280', icon: '#6b7280' },
         computer: { border: '#7c3aed', icon: '#7c3aed' },
         cpl:      { border: '#b45309', icon: '#b45309' },
+        docker:   { border: '#2496ED', icon: '#2496ED' },
         generic:  { border: '#6b7280', icon: '#6b7280' },
         groupRect:{ border: '#0284c7', icon: '#0284c7' },
       },
@@ -215,6 +218,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:  { border: '#8888ff', icon: '#8888ff' },
         computer: { border: '#ff00ff', icon: '#ff00ff' },
         cpl:      { border: '#ffff00', icon: '#ffff00' },
+        docker:   { border: '#00aaff', icon: '#00aaff' },
         generic:  { border: '#8888ff', icon: '#8888ff' },
         groupRect:{ border: '#00ffff', icon: '#00ffff' },
       },
@@ -268,6 +272,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:  { border: '#005500', icon: '#005500' },
         computer: { border: '#008822', icon: '#008822' },
         cpl:      { border: '#66ff33', icon: '#66ff33' },
+        docker:   { border: '#00cc88', icon: '#00cc88' },
         generic:  { border: '#006600', icon: '#006600' },
         groupRect:{ border: '#00ff41', icon: '#00ff41' },
       },