feat(builder): item 16 — context menu FA icon per action

Every menu item now has an FA icon (previously only "Ask Sitesmith" did,
leaving the rest visually misaligned): Duplicate fa-clone, Copy
fa-files-o, Paste fa-clipboard, Move Up/Down fa-arrow-up/down, Select
Parent fa-level-up, Delete fa-trash (kept its danger-red color). The
clipboard-group / structure-group separator already existed via
dividerAfter — no structural change needed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/panels/context-menu/ContextMenu.tsx

@@ -199,18 +199,21 @@ export const ContextMenu: React.FC<ContextMenuProps> = ({
     },
     {
       label: 'Duplicate',
+      icon: 'clone',
       shortcut: 'Ctrl+D',
       action: duplicate,
       disabled: isRoot,
     },
     {
       label: 'Copy',
+      icon: 'files-o',
       shortcut: 'Ctrl+C',
       action: copyNode,
       disabled: isRoot,
     },
     {
       label: 'Paste',
+      icon: 'clipboard',
       shortcut: 'Ctrl+V',
       action: pasteNode,
       disabled: !getClipboardNodeId(),
@@ -218,22 +221,26 @@ export const ContextMenu: React.FC<ContextMenuProps> = ({
     },
     {
       label: 'Move Up',
+      icon: 'arrow-up',
       action: moveUp,
       disabled: isRoot,
     },
     {
       label: 'Move Down',
+      icon: 'arrow-down',
       action: moveDown,
       disabled: isRoot,
     },
     {
       label: 'Select Parent',
+      icon: 'level-up',
       action: selectParent,
       disabled: isRoot,
       dividerAfter: true,
     },
     {
       label: 'Delete',
+      icon: 'trash',
       shortcut: 'Del',
       action: deleteNode,
       danger: true,