feat: add GRANITE as fourth workflow type in Ivanti queue

- Add GRANITE to VALID_WORKFLOW_TYPES in backend (no vendor required, same as CARD)
- Update vendor validation and error messages across all endpoints (single add, batch, PUT, redirect)
- Add GRANITE option to RedirectModal with warm slate color (#A1887F)
- Rename QueuePanel CARD section to Inventory, group CARD + GRANITE with sub-divider
- Add GRANITE to AddToQueuePopover and SelectionToolbar
- Update spec docs (requirements, design, tasks)

frontend/src/components/RedirectModal.js

@@ -4,9 +4,10 @@ import { CornerUpRight, X, Loader, AlertCircle } from 'lucide-react';
 const API_BASE = process.env.REACT_APP_API_BASE || 'http://localhost:3001/api';
 
 const WORKFLOW_OPTIONS = [
-  { key: 'FP',     label: 'FP',     col: '#F59E0B', rgb: '245,158,11' },
-  { key: 'Archer', label: 'Archer', col: '#0EA5E9', rgb: '14,165,233' },
-  { key: 'CARD',   label: 'CARD',   col: '#10B981', rgb: '16,185,129' },
+  { key: 'FP',      label: 'FP',      col: '#F59E0B', rgb: '245,158,11' },
+  { key: 'Archer',  label: 'Archer',  col: '#0EA5E9', rgb: '14,165,233' },
+  { key: 'CARD',    label: 'CARD',    col: '#10B981', rgb: '16,185,129' },
+  { key: 'GRANITE', label: 'GRANITE', col: '#A1887F', rgb: '161,136,127' },
 ];
 
 export default function RedirectModal({ item, onClose, onRedirect }) {