User-supplied asset ids; brand on product; strain is the name

Four UX changes after using the rework for a bit:

1. Asset ids are 6-digit numbers from a roll of physical labels — server
   no longer generates them. POST /api/inventory requires assetId; the
   add-inventory form has a digits-only input that auto-focuses on entry.
2. Strain and product name are the same thing. Drop products.name; the
   strain's name supplies the display. Product creation just asks for
   "Name (strain)" and matches/creates a strain by that name.
3. Brand moves from inventory_items to products. SKUs are brand-specific,
   so all instances of a product share the brand. Brand selector lives
   on the product create/edit form, not the per-instance form.
4. Scanning an unknown SKU on the add-inventory step now opens the
   create-product subform with the SKU prefilled — one less click.

Migration: detect prior shape (products.name column present) and rename
products/inventory_items/audits to *_v1 archives, recreate empty.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/components/ScanField.tsx

@@ -14,11 +14,16 @@ export function ScanField({
   items,
   products,
   onMatch,
+  onScanNoMatch,
   matchedLabel,
 }: {
   items: Item[];
   products?: Product[];
   onMatch: (result: ScanResult) => void;
+  // Fired once after a debounce when the scanned text doesn't resolve to
+  // any known asset id or SKU. The parent can use the raw value (e.g. to
+  // open a "create new product" form prefilled with the scanned SKU).
+  onScanNoMatch?: (raw: string) => void;
   matchedLabel: string | null;
 }) {
   const [scan, setScan] = useState("");
@@ -32,11 +37,10 @@ export function ScanField({
     }
     const hit = lookup(trimmed, items, products);
     if (hit) {
+      const label = hit.kind === "item" ? hit.item.name : hit.product.sku;
       onMatch(hit);
       setScan("");
-      const name =
-        hit.kind === "item" ? hit.item.name : hit.product.name;
-      setFeedback({ type: "matched", text: `Matched ${name}` });
+      setFeedback({ type: "matched", text: `Matched ${label}` });
     }
   }, [scan]); // eslint-disable-line react-hooks/exhaustive-deps
 
@@ -45,9 +49,15 @@ export function ScanField({
   useEffect(() => {
     if (!scan.trim() || feedback?.type === "matched") return;
     const timer = setTimeout(() => {
-      const trimmed = scan.trim().toLowerCase();
-      if (!lookup(trimmed, items, products)) {
-        setFeedback({ type: "miss", text: "No asset id or SKU matches that." });
+      const raw = scan.trim();
+      if (!lookup(raw.toLowerCase(), items, products)) {
+        if (onScanNoMatch) {
+          onScanNoMatch(raw);
+          setScan("");
+          setFeedback(null);
+        } else {
+          setFeedback({ type: "miss", text: "No asset id or SKU matches that." });
+        }
       }
     }, 400);
     return () => clearTimeout(timer);