CUB-129: Build Print Jobs list page

- Add PrintJob types (PrintJob, PrintJobFilter) with status union type
- Add printJobService.ts using axios + TanStack Query
- Build PrintJobsPage.tsx with:
  - Desktop table: job name, printer, color-coded status badge, started time, duration, filament used, cost
  - Mobile card layout with grid-based info display
  - Filter by status (pending/printing/completed/failed)
  - Filter by printer name
  - Sort by any column (name, started_at, duration, filament, cost)
  - Pagination with 20 per page
  - Loading spinner, error with retry, empty state
  - Client-side text search by job/printer name
  - Duration formatting (h/m/s)
- Add navigation bar in App.tsx with Inventory + Print Jobs tabs using NavLink

frontend/src/App.tsx

@@ -1,9 +1,28 @@
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
-import { BrowserRouter, Routes, Route } from 'react-router-dom'
+import { BrowserRouter, Routes, Route, NavLink } from 'react-router-dom'
+import { Box, Printer } from 'lucide-react'
 import InventoryPage from './pages/InventoryPage'
+import PrintJobsPage from './pages/PrintJobsPage'
 
 const queryClient = new QueryClient()
 
+function NavItem({ to, icon: Icon, label }: { to: string; icon: React.ComponentType<{ size?: number }>; label: string }) {
+  return (
+    <NavLink
+      to={to}
+      className={({ isActive }) =>
+        `inline-flex items-center gap-2 rounded-lg px-3 py-2 text-sm font-medium transition-colors ${
+          isActive
+            ? 'bg-emerald-600/20 text-emerald-300 border border-emerald-700'
+            : 'text-slate-400 hover:text-slate-200 hover:bg-slate-700/50'
+        }`
+      }
+    >
+      <Icon size={16} /> {label}
+    </NavLink>
+  )
+}
+
 export default function App() {
   return (
     <QueryClientProvider client={queryClient}>
@@ -12,10 +31,15 @@ export default function App() {
           <header className="bg-slate-800 border-b border-slate-700 px-4 py-3 flex items-center gap-3 sticky top-0 z-20">
             <div className="w-8 h-8 rounded bg-emerald-500 flex items-center justify-center text-slate-900 font-bold text-lg">E</div>
             <h1 className="text-lg font-semibold">Extrudex</h1>
+            <nav className="ml-6 flex items-center gap-1">
+              <NavItem to="/" icon={Box} label="Inventory" />
+              <NavItem to="/print-jobs" icon={Printer} label="Print Jobs" />
+            </nav>
           </header>
           <main className="p-4">
             <Routes>
               <Route path="/" element={<InventoryPage />} />
+              <Route path="/print-jobs" element={<PrintJobsPage />} />
             </Routes>
           </main>
         </div>

frontend/src/pages/PrintJobsPage.tsx

@@ -0,0 +1,283 @@
+import { useState, useMemo } from 'react'
+import { useQuery } from '@tanstack/react-query'
+import { Search, Filter, ChevronLeft, ChevronRight, Loader2 } from 'lucide-react'
+import { fetchPrintJobs } from '../services/printJobService'
+import type { PrintJob, PrintJobFilter, PrintJobStatus } from '../types/printJob'
+
+const PAGE_SIZE = 20
+
+type SortField = 'name' | 'started_at' | 'duration_seconds' | 'filament_grams_used' | 'cost_usd'
+type SortDir = 'asc' | 'desc'
+
+// ── Status helpers ────────────────────────────────────────────────────────────
+
+const STATUS_CONFIG: Record<PrintJobStatus, { label: string; badge: string; icon: string }> = {
+  pending:   { label: 'Pending',   badge: 'bg-slate-700 text-slate-300 border-slate-600',       icon: '⏳' },
+  printing:  { label: 'Printing',  badge: 'bg-blue-900/40 text-blue-300 border-blue-700',       icon: '🖨️' },
+  completed: { label: 'Completed', badge: 'bg-emerald-900/30 text-emerald-300 border-emerald-700', icon: '✅' },
+  failed:    { label: 'Failed',    badge: 'bg-red-900/40 text-red-300 border-red-700',          icon: '❌' },
+}
+
+function StatusBadge({ status }: { status: PrintJobStatus }) {
+  const cfg = STATUS_CONFIG[status] ?? STATUS_CONFIG.pending
+  return (
+    <span className={`inline-flex items-center gap-1 rounded-full border px-2 py-0.5 text-xs font-medium ${cfg.badge}`}>
+      <span className="text-xs">{cfg.icon}</span> {cfg.label}
+    </span>
+  )
+}
+
+// ── Duration formatter ────────────────────────────────────────────────────────
+
+function formatDuration(totalSeconds?: number): string {
+  if (totalSeconds == null || totalSeconds <= 0) return '—'
+  const h = Math.floor(totalSeconds / 3600)
+  const m = Math.floor((totalSeconds % 3600) / 60)
+  const s = totalSeconds % 60
+  if (h > 0) return `${h}h ${m}m`
+  if (m > 0) return `${m}m ${s}s`
+  return `${s}s`
+}
+
+function formatDateTime(iso: string): string {
+  const d = new Date(iso)
+  return d.toLocaleString(undefined, {
+    month: 'short', day: 'numeric',
+    hour: 'numeric', minute: '2-digit',
+  })
+}
+
+// ── Component ─────────────────────────────────────────────────────────────────
+
+export default function PrintJobsPage() {
+  const [search, setSearch] = useState('')
+  const [statusFilter, setStatusFilter] = useState<PrintJobStatus | ''>('')
+  const [printerFilter, setPrinterFilter] = useState('')
+  const [sortBy, setSortBy] = useState<SortField>('started_at')
+  const [sortDir, setSortDir] = useState<SortDir>('desc')
+  const [page, setPage] = useState(0)
+
+  const filter: PrintJobFilter = useMemo(() => ({
+    status: statusFilter || undefined,
+    printer: printerFilter || undefined,
+    sort_by: sortBy,
+    sort_dir: sortDir,
+    limit: PAGE_SIZE,
+    offset: page * PAGE_SIZE,
+  }), [statusFilter, printerFilter, sortBy, sortDir, page])
+
+  const { data, isLoading, error, refetch } = useQuery({
+    queryKey: ['printJobs', filter],
+    queryFn: () => fetchPrintJobs(filter),
+  })
+
+  const jobs = data?.data ?? []
+  const total = data?.total ?? 0
+  const totalPages = Math.max(1, Math.ceil(total / PAGE_SIZE))
+
+  // Client-side search (name + printer name)
+  const filtered = useMemo(() => {
+    if (!search.trim()) return jobs
+    const q = search.toLowerCase()
+    return jobs.filter(
+      (j: PrintJob) =>
+        j.name.toLowerCase().includes(q) ||
+        j.printer_name.toLowerCase().includes(q)
+    )
+  }, [jobs, search])
+
+  const handleSort = (field: SortField) => {
+    if (sortBy === field) {
+      setSortDir(prev => (prev === 'asc' ? 'desc' : 'asc'))
+    } else {
+      setSortBy(field)
+      setSortDir('asc')
+    }
+    setPage(0)
+  }
+
+  const SortIndicator = ({ field }: { field: SortField }) => {
+    if (sortBy !== field) return <span className="text-slate-600 ml-1">↕</span>
+    return <span className="text-emerald-400 ml-1">{sortDir === 'asc' ? '↑' : '↓'}</span>
+  }
+
+  return (
+    <div className="space-y-4">
+      {/* Header */}
+      <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-3">
+        <div>
+          <h2 className="text-xl font-bold text-slate-100">Print Jobs</h2>
+          <p className="text-sm text-slate-400">{total} job(s) total</p>
+        </div>
+      </div>
+
+      {/* Filters */}
+      <div className="flex flex-col lg:flex-row gap-3">
+        {/* Search */}
+        <div className="relative flex-1">
+          <Search size={16} className="absolute left-3 top-1/2 -translate-y-1/2 text-slate-400" />
+          <input
+            type="text"
+            placeholder="Search by job or printer name…"
+            value={search}
+            onChange={e => { setSearch(e.target.value); setPage(0) }}
+            className="w-full rounded-lg bg-slate-800 border border-slate-700 pl-9 pr-3 py-2 text-sm text-slate-100 placeholder-slate-500 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:border-emerald-500"
+          />
+        </div>
+
+        {/* Status filter */}
+        <select
+          value={statusFilter}
+          onChange={e => { setStatusFilter(e.target.value as PrintJobStatus | ''); setPage(0) }}
+          className="rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 focus:outline-none focus:ring-2 focus:ring-emerald-500"
+        >
+          <option value="">All Statuses</option>
+          <option value="pending">Pending</option>
+          <option value="printing">Printing</option>
+          <option value="completed">Completed</option>
+          <option value="failed">Failed</option>
+        </select>
+
+        {/* Printer filter */}
+        <input
+          type="text"
+          placeholder="Filter by printer…"
+          value={printerFilter}
+          onChange={e => { setPrinterFilter(e.target.value); setPage(0) }}
+          className="rounded-lg bg-slate-800 border border-slate-700 px-3 py-2 text-sm text-slate-100 placeholder-slate-500 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:border-emerald-500 min-w-[160px]"
+        />
+
+        {/* Filter indicator */}
+        {(statusFilter || printerFilter) && (
+          <span className="inline-flex items-center gap-1 rounded-lg bg-emerald-900/30 border border-emerald-700 px-3 py-2 text-xs text-emerald-300">
+            <Filter size={14} />
+            {[statusFilter && `Status: ${statusFilter}`, printerFilter && `Printer: ${printerFilter}`].filter(Boolean).join(' · ')}
+          </span>
+        )}
+      </div>
+
+      {/* Loading / Error */}
+      {isLoading && (
+        <div className="flex items-center justify-center py-12 gap-2 text-slate-400">
+          <Loader2 size={18} className="animate-spin" /> Loading print jobs…
+        </div>
+      )}
+      {error && (
+        <div className="text-center py-12 text-red-400">
+          Failed to load print jobs.
+          <button onClick={() => refetch()} className="ml-2 underline hover:text-red-300">Retry</button>
+        </div>
+      )}
+
+      {/* Desktop Table */}
+      {!isLoading && !error && (
+        <>
+          <div className="hidden md:block overflow-x-auto rounded-lg border border-slate-700">
+            <table className="w-full text-sm">
+              <thead className="bg-slate-800 text-slate-300">
+                <tr>
+                  <th className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('name')}>
+                    Job <SortIndicator field="name" />
+                  </th>
+                  <th className="px-4 py-3 text-left font-semibold">Printer</th>
+                  <th className="px-4 py-3 text-left font-semibold">Status</th>
+                  <th className="px-4 py-3 text-left font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('started_at')}>
+                    Started <SortIndicator field="started_at" />
+                  </th>
+                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('duration_seconds')}>
+                    Duration <SortIndicator field="duration_seconds" />
+                  </th>
+                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('filament_grams_used')}>
+                    Filament <SortIndicator field="filament_grams_used" />
+                  </th>
+                  <th className="px-4 py-3 text-right font-semibold cursor-pointer select-none hover:text-slate-100" onClick={() => handleSort('cost_usd')}>
+                    Cost <SortIndicator field="cost_usd" />
+                  </th>
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-slate-700">
+                {filtered.length === 0 && (
+                  <tr>
+                    <td colSpan={7} className="px-4 py-8 text-center text-slate-500">No print jobs found.</td>
+                  </tr>
+                )}
+                {filtered.map((job: PrintJob) => (
+                  <tr key={job.id} className="bg-slate-800/50 hover:bg-slate-700/50 transition-colors">
+                    <td className="px-4 py-3 font-medium text-slate-100">{job.name}</td>
+                    <td className="px-4 py-3 text-slate-300">{job.printer_name}</td>
+                    <td className="px-4 py-3"><StatusBadge status={job.status} /></td>
+                    <td className="px-4 py-3 text-slate-300">{formatDateTime(job.started_at)}</td>
+                    <td className="px-4 py-3 text-right tabular-nums text-slate-300">{formatDuration(job.duration_seconds)}</td>
+                    <td className="px-4 py-3 text-right tabular-nums text-slate-300">{job.filament_grams_used != null ? `${job.filament_grams_used.toLocaleString()} g` : '—'}</td>
+                    <td className="px-4 py-3 text-right tabular-nums text-slate-300">{job.cost_usd != null ? `$${job.cost_usd.toFixed(2)}` : '—'}</td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+
+          {/* Mobile Cards */}
+          <div className="md:hidden space-y-3">
+            {filtered.length === 0 && (
+              <div className="text-center py-12 text-slate-500">No print jobs found.</div>
+            )}
+            {filtered.map((job: PrintJob) => (
+              <div key={job.id} className="rounded-lg border border-slate-700 bg-slate-800 p-4 space-y-3">
+                <div className="flex items-start justify-between">
+                  <div>
+                    <div className="font-semibold text-slate-100">{job.name}</div>
+                    <div className="text-xs text-slate-400 mt-0.5">{job.printer_name}</div>
+                  </div>
+                  <StatusBadge status={job.status} />
+                </div>
+
+                <div className="grid grid-cols-2 gap-2 text-sm">
+                  <div>
+                    <span className="text-slate-500 text-xs">Started</span>
+                    <div className="text-slate-300">{formatDateTime(job.started_at)}</div>
+                  </div>
+                  <div>
+                    <span className="text-slate-500 text-xs">Duration</span>
+                    <div className="text-slate-300 tabular-nums">{formatDuration(job.duration_seconds)}</div>
+                  </div>
+                  <div>
+                    <span className="text-slate-500 text-xs">Filament</span>
+                    <div className="text-slate-300 tabular-nums">{job.filament_grams_used != null ? `${job.filament_grams_used.toLocaleString()} g` : '—'}</div>
+                  </div>
+                  <div>
+                    <span className="text-slate-500 text-xs">Cost</span>
+                    <div className="text-slate-300 tabular-nums">{job.cost_usd != null ? `$${job.cost_usd.toFixed(2)}` : '—'}</div>
+                  </div>
+                </div>
+              </div>
+            ))}
+          </div>
+
+          {/* Pagination */}
+          <div className="flex items-center justify-between pt-2">
+            <span className="text-sm text-slate-400">
+              Showing {total === 0 ? 0 : page * PAGE_SIZE + 1}–{Math.min((page + 1) * PAGE_SIZE, total)} of {total}
+            </span>
+            <div className="flex items-center gap-2">
+              <button
+                onClick={() => setPage(p => Math.max(0, p - 1))}
+                disabled={page === 0}
+                className="p-2 rounded-lg bg-slate-800 border border-slate-700 text-slate-300 hover:bg-slate-700 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
+              >
+                <ChevronLeft size={16} />
+              </button>
+              <span className="text-sm text-slate-300 tabular-nums">{page + 1} / {totalPages}</span>
+              <button
+                onClick={() => setPage(p => Math.min(totalPages - 1, p + 1))}
+                disabled={page >= totalPages - 1}
+                className="p-2 rounded-lg bg-slate-800 border border-slate-700 text-slate-300 hover:bg-slate-700 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
+              >
+                <ChevronRight size={16} />
+              </button>
+            </div>
+          </div>
+        </>
+      )}
+    </div>
+  )
+}

frontend/src/services/printJobService.ts

@@ -0,0 +1,17 @@
+import axios from 'axios'
+import type { PrintJob, ListResponse, PrintJobFilter } from '../types/printJob'
+
+const API_BASE = '/api'
+
+export async function fetchPrintJobs(filter: PrintJobFilter): Promise<ListResponse<PrintJob>> {
+  const params = new URLSearchParams()
+  if (filter.status) params.set('status', filter.status)
+  if (filter.printer) params.set('printer', filter.printer)
+  if (filter.sort_by) params.set('sort_by', filter.sort_by)
+  if (filter.sort_dir) params.set('sort_dir', filter.sort_dir)
+  if (filter.limit !== undefined) params.set('limit', String(filter.limit))
+  if (filter.offset !== undefined) params.set('offset', String(filter.offset))
+
+  const res = await axios.get<ListResponse<PrintJob>>(`${API_BASE}/print-jobs?${params.toString()}`)
+  return res.data
+}

frontend/src/types/printJob.ts

@@ -0,0 +1,32 @@
+// Print Job domain types
+
+export type PrintJobStatus = 'pending' | 'printing' | 'completed' | 'failed'
+
+export interface PrintJob {
+  id: number
+  name: string
+  printer_name: string
+  status: PrintJobStatus
+  started_at: string
+  duration_seconds?: number
+  filament_grams_used?: number
+  cost_usd?: number
+  created_at: string
+  updated_at: string
+}
+
+export interface ListResponse<T> {
+  data: T[]
+  total: number
+  limit: number
+  offset: number
+}
+
+export interface PrintJobFilter {
+  status?: PrintJobStatus
+  printer?: string
+  sort_by?: string
+  sort_dir?: 'asc' | 'desc'
+  limit?: number
+  offset?: number
+}