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/api.ts

@@ -18,11 +18,11 @@ export const api = {
   // Catalog: products
   createProduct: (body: {
     sku: string;
-    name: string;
     type: string;
     kind: "bulk" | "discrete";
     strainId?: string | null;
     strainName?: string;
+    brandId?: string | null;
     defaultThc?: number;
     defaultCbd?: number;
     defaultTotalCannabinoids?: number;
@@ -31,10 +31,11 @@ export const api = {
   updateProduct: (
     id: string,
     body: Partial<{
-      name: string;
       type: string;
       kind: "bulk" | "discrete";
       strainId: string | null;
+      strainName: string;
+      brandId: string | null;
     }>,
   ) =>
     request<{ ok: true }>(`/products/${id}`, {
@@ -62,8 +63,8 @@ export const api = {
 
   // Inventory items (instances)
   createInventoryItem: (body: {
+    assetId: string;
     productId: string;
-    brandId?: string | null;
     shopId?: string | null;
     binId?: string | null;
     price: number;
@@ -83,7 +84,6 @@ export const api = {
   updateInventoryItem: (
     id: string,
     body: Partial<{
-      brandId: string | null;
       shopId: string | null;
       binId: string | null;
       price: number;