feat: chat agent knows current page context (order/product)

Frontend: Layout extracts order/product UUID from URL path and passes
to ChatPanel as contextType/contextId. When on /orders/{uuid}, the
chat knows which order you're viewing.

Backend: System prompt now loads actual entity data for the context:
- Order: order_number, status, line counts (completed/processing/failed)
- Product: name, PIM-ID, category, STEP file status

The AI understands "this order", "current product" etc. Example:
"What's the status of this order?" → agent knows you mean SA-2026-00164

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/layout/Layout.tsx

@@ -1,4 +1,4 @@
-import { Outlet, NavLink, useNavigate, Link } from 'react-router-dom'
+import { Outlet, NavLink, useNavigate, Link, useLocation } from 'react-router-dom'
 import { LayoutDashboard, Package, Settings, LogOut, FlaskConical, Activity, Library, Plus, SlidersHorizontal, Building2, GitBranch, Image, BellRing, Receipt, Server, Upload, Menu, X, MessageSquare } from 'lucide-react'
 import { useAuthStore, isAdmin as checkIsAdmin, isPrivileged as checkIsPrivileged } from '../../store/auth'
 import { clsx } from 'clsx'
@@ -36,9 +36,20 @@ const adminOnlyNav = [
 export default function Layout() {
   const { user, logout } = useAuthStore()
   const navigate = useNavigate()
+  const location = useLocation()
   const [sidebarOpen, setSidebarOpen] = useState(false)
   const [chatOpen, setChatOpen] = useState(false)
 
+  // Extract page context from URL for the chat agent
+  const chatContext = (() => {
+    const path = location.pathname
+    const orderMatch = path.match(/^\/orders\/([0-9a-f-]{36})/)
+    if (orderMatch) return { type: 'order', id: orderMatch[1] }
+    const productMatch = path.match(/^\/products\/([0-9a-f-]{36})/)
+    if (productMatch) return { type: 'product', id: productMatch[1] }
+    return { type: undefined, id: undefined }
+  })()
+
   const { data: activity } = useQuery({
     queryKey: ['worker-activity'],
     queryFn: getWorkerActivity,
@@ -260,7 +271,7 @@ export default function Layout() {
       )}
 
       {/* Chat panel */}
-      {chatOpen && <ChatPanel open={chatOpen} onClose={() => setChatOpen(false)} />}
+      {chatOpen && <ChatPanel open={chatOpen} onClose={() => setChatOpen(false)} contextType={chatContext.type} contextId={chatContext.id} />}
     </div>
   )
 }