feat: add quantity field to items schema

Add integer quantity column (default 1) to the items table, generate
the corresponding Drizzle migration, and extend createItemSchema /
updateItemSchema with an optional positive-integer quantity field.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

drizzle/0008_loving_colossus.sql

@@ -0,0 +1 @@
+ALTER TABLE `items` ADD `quantity` integer DEFAULT 1 NOT NULL;

src/db/schema.ts

@@ -21,6 +21,7 @@ export const items = sqliteTable("items", {
 	productUrl: text("product_url"),
 	imageFilename: text("image_filename"),
 	imageSourceUrl: text("image_source_url"),
+	quantity: integer("quantity").notNull().default(1),
 	createdAt: integer("created_at", { mode: "timestamp" })
 		.notNull()
 		.$defaultFn(() => new Date()),

src/shared/schemas.ts

@@ -9,6 +9,7 @@ export const createItemSchema = z.object({
 	productUrl: z.string().url().optional().or(z.literal("")),
 	imageFilename: z.string().optional(),
 	imageSourceUrl: z.string().url().optional().or(z.literal("")),
+	quantity: z.number().int().positive().optional(),
 });
 
 export const updateItemSchema = createItemSchema.partial().extend({