feat: material alias seeds expansion, bulk product delete, dashboard stats widgets

- Material alias seeds: 95 → 855 aliases covering German variants, DIN standards,
  Werkstoffnummern, industry terms, English equivalents, polymer abbreviations
- Batch product delete/deactivate endpoint (POST /products/batch-delete)
- Multi-select UI on Products page with floating action bar
- Dashboard: RenderThroughput + MaterialCoverage widgets
- Dashboard stats endpoint (GET /admin/dashboard-stats)

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

frontend/src/pages/ProductLibrary.tsx

@@ -1,14 +1,14 @@
 import { useState, useEffect, useMemo } from 'react'
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
+import { useQuery, useQueryClient } from '@tanstack/react-query'
 import { useNavigate } from 'react-router-dom'
 import {
   Library, Search, Box, CheckCircle2, Clock, AlertTriangle,
   LayoutGrid, List, Trash2, X, ArrowUpDown,
+  CheckSquare, Square, EyeOff, Loader2,
 } from 'lucide-react'
 import { toast } from 'sonner'
-import { listProducts, deleteProduct } from '../api/products'
+import { listProducts, batchDeleteProducts } from '../api/products'
 import type { Product } from '../api/products'
-import ConfirmModal from '../components/ConfirmModal'
 
 const CATEGORY_LABELS: Record<string, string> = {
   TRB: 'TRB',
@@ -123,7 +123,6 @@ export default function ProductLibraryPage() {
   const [sortBy, setSortBy] = useState<'pim_id' | 'name' | 'status'>('pim_id')
   const [view, setView] = useState<'grid' | 'table'>('grid')
   const [selected, setSelected] = useState<Set<string>>(new Set())
-  const [confirmState, setConfirmState] = useState<{ open: boolean; title: string; message: string; onConfirm: () => void }>({ open: false, title: '', message: '', onConfirm: () => {} })
 
   // Debounce search input (300ms)
   useEffect(() => {
@@ -169,31 +168,41 @@ export default function ProductLibraryPage() {
     setSelected(allSelected ? new Set() : new Set(products.map((p) => p.id)))
   }
 
-  // ── Bulk delete ────────────────────────────────────────────────────────
-  const deleteMut = useMutation({
-    mutationFn: async (ids: string[]) => {
-      await Promise.all(ids.map((id) => deleteProduct(id, true)))
-    },
-    onSuccess: (_, ids) => {
-      toast.success(`${ids.length} product${ids.length > 1 ? 's' : ''} deleted`)
-      setSelected(new Set())
-      qc.invalidateQueries({ queryKey: ['products'] })
-    },
-    onError: (e: any) => toast.error(e.response?.data?.detail || 'Delete failed'),
-  })
+  // ── Bulk actions ──────────────────────────────────────────────────────
+  const [batchBusy, setBatchBusy] = useState(false)
+  const [confirmDeleteHard, setConfirmDeleteHard] = useState(false)
 
-  const handleDeleteSelected = () => {
+  const handleDeactivateSelected = async () => {
     const ids = [...selected]
     if (!ids.length) return
-    setConfirmState({
-      open: true,
-      title: `Delete ${ids.length} product${ids.length > 1 ? 's' : ''}`,
-      message: 'This cannot be undone.',
-      onConfirm: () => {
-        deleteMut.mutate(ids)
-        setConfirmState((s) => ({ ...s, open: false }))
-      },
-    })
+    setBatchBusy(true)
+    try {
+      const result = await batchDeleteProducts(ids, false)
+      toast.success(`Deactivated ${result.deleted} product${result.deleted !== 1 ? 's' : ''}`)
+      setSelected(new Set())
+      qc.invalidateQueries({ queryKey: ['products'] })
+    } catch (e: any) {
+      toast.error(e.response?.data?.detail || 'Deactivate failed')
+    } finally {
+      setBatchBusy(false)
+    }
+  }
+
+  const handleHardDeleteSelected = async () => {
+    const ids = [...selected]
+    if (!ids.length) return
+    setBatchBusy(true)
+    try {
+      const result = await batchDeleteProducts(ids, true)
+      toast.success(`Permanently deleted ${result.deleted} product${result.deleted !== 1 ? 's' : ''}`)
+      setSelected(new Set())
+      setConfirmDeleteHard(false)
+      qc.invalidateQueries({ queryKey: ['products'] })
+    } catch (e: any) {
+      toast.error(e.response?.data?.detail || 'Delete failed')
+    } finally {
+      setBatchBusy(false)
+    }
   }
 
   return (
@@ -204,9 +213,21 @@ export default function ProductLibraryPage() {
           <Library size={22} className="text-accent" />
           <div>
             <h1 className="text-2xl font-bold text-content">Product Library</h1>
-            <p className="text-sm text-content-muted">
-              {products ? `${products.length} products` : isLoading ? 'Loading…' : '0 products'}
-            </p>
+            <div className="flex items-center gap-3 text-sm text-content-muted">
+              <span>{products ? `${products.length} products` : isLoading ? 'Loading\u2026' : '0 products'}</span>
+              {products && products.length > 0 && (
+                <button
+                  onClick={toggleAll}
+                  className="flex items-center gap-1 hover:text-content transition-colors"
+                >
+                  {allSelected ? <CheckSquare size={13} /> : <Square size={13} />}
+                  {allSelected ? 'Deselect all' : 'Select all'}
+                </button>
+              )}
+              {selected.size > 0 && (
+                <span className="text-accent font-medium">{selected.size} selected</span>
+              )}
+            </div>
           </div>
         </div>
 
@@ -433,35 +454,63 @@ export default function ProductLibraryPage() {
         </div>
       )}
 
-      <ConfirmModal
-        open={confirmState.open}
-        title={confirmState.title}
-        message={confirmState.message}
-        onConfirm={confirmState.onConfirm}
-        onCancel={() => setConfirmState((s) => ({ ...s, open: false }))}
-      />
 
-      {/* ── Floating action bar ───────────────────────────────────────── */}
+      {/* ── Floating selection action bar (MediaBrowser pattern) ───── */}
       {selected.size > 0 && (
         <div
-          className="fixed bottom-6 z-50 flex items-center gap-4 px-5 py-3 bg-gray-900 text-white rounded-2xl shadow-2xl ring-1 ring-white/10"
-          style={{ left: 'calc(240px + (100vw - 240px) / 2)', transform: 'translateX(-50%)' }}
+          className="fixed bottom-6 left-1/2 -translate-x-1/2 z-40 flex items-center gap-3 px-5 py-3 rounded-xl shadow-2xl border border-border-default"
+          style={{ backgroundColor: 'var(--color-bg-surface)' }}
         >
-          <span className="text-sm font-medium">
-            {selected.size} selected
+          <span className="text-sm font-medium text-content">
+            {selected.size} product{selected.size !== 1 ? 's' : ''} selected
           </span>
+          <div className="w-px h-5 bg-border-default" />
           <button
-            onClick={handleDeleteSelected}
-            disabled={deleteMut.isPending}
-            className="flex items-center gap-1.5 px-3 py-1.5 bg-red-600 hover:bg-red-700 rounded text-sm font-medium transition-colors disabled:opacity-50"
+            onClick={handleDeactivateSelected}
+            disabled={batchBusy}
+            className="flex items-center gap-1.5 text-sm font-medium text-content-secondary hover:text-content transition-colors disabled:opacity-50"
           >
-            <Trash2 size={14} />
-            {deleteMut.isPending ? 'Deleting\u2026' : 'Delete'}
+            {batchBusy && !confirmDeleteHard
+              ? <><Loader2 size={14} className="animate-spin" /> Deactivating&hellip;</>
+              : <><EyeOff size={14} /> Deactivate</>
+            }
           </button>
+          <div className="w-px h-5 bg-border-default" />
+          {confirmDeleteHard ? (
+            <div className="flex items-center gap-2">
+              <span className="text-sm text-red-500 font-medium">
+                Delete {selected.size} permanently?
+              </span>
+              <button
+                onClick={handleHardDeleteSelected}
+                disabled={batchBusy}
+                className="flex items-center gap-1 text-sm font-medium text-white bg-red-500 hover:bg-red-600 px-2.5 py-1 rounded transition-colors disabled:opacity-50"
+              >
+                {batchBusy
+                  ? <><Loader2 size={12} className="animate-spin" /> Deleting&hellip;</>
+                  : <><Trash2 size={12} /> Confirm</>
+                }
+              </button>
+              <button
+                onClick={() => setConfirmDeleteHard(false)}
+                disabled={batchBusy}
+                className="text-sm text-content-muted hover:text-content transition-colors disabled:opacity-50"
+              >
+                Cancel
+              </button>
+            </div>
+          ) : (
+            <button
+              onClick={() => setConfirmDeleteHard(true)}
+              className="flex items-center gap-1.5 text-sm font-medium text-red-500 hover:text-red-400 transition-colors"
+            >
+              <Trash2 size={14} /> Delete permanently
+            </button>
+          )}
+          <div className="w-px h-5 bg-border-default" />
           <button
-            onClick={() => setSelected(new Set())}
-            className="flex items-center gap-1 px-2 py-1.5 text-gray-400 hover:text-white text-sm transition-colors"
-            title="Clear selection"
+            onClick={() => { setSelected(new Set()); setConfirmDeleteHard(false) }}
+            className="flex items-center gap-1 text-sm text-content-muted hover:text-content transition-colors"
           >
             <X size={14} /> Clear
           </button>