feat(18-02): implement global item service, seed script, and seed integration

- searchGlobalItems with LIKE-based case-insensitive search and wildcard escaping
- getGlobalItemWithOwnerCount with owner count from junction table
- linkItemToGlobal/unlinkItemFromGlobal for item-global linking
- seedGlobalItems idempotent seed from JSON catalog
- Integrated seed into seedDefaults startup

src/db/seed-global-items.ts

@@ -0,0 +1,27 @@
+import { db as prodDb } from "./index.ts";
+import { globalItems } from "./schema.ts";
+import seedData from "./global-items-seed.json";
+
+type Db = typeof prodDb;
+
+/**
+ * Seed the global items table with initial bikepacking gear data.
+ * Idempotent: skips if any rows already exist.
+ */
+export function seedGlobalItems(db: Db = prodDb) {
+	const existing = db.select().from(globalItems).limit(1).all();
+	if (existing.length > 0) return;
+
+	for (const item of seedData) {
+		db.insert(globalItems)
+			.values({
+				brand: item.brand,
+				model: item.model,
+				category: item.category ?? null,
+				weightGrams: item.weightGrams ?? null,
+				priceCents: item.priceCents ?? null,
+				description: item.description ?? null,
+			})
+			.run();
+	}
+}

src/db/seed.ts

@@ -1,5 +1,6 @@
 import { db } from "./index.ts";
 import { categories } from "./schema.ts";
+import { seedGlobalItems } from "./seed-global-items.ts";
 
 export function seedDefaults() {
 	const existing = db.select().from(categories).all();
@@ -11,4 +12,7 @@ export function seedDefaults() {
 			})
 			.run();
 	}
+
+	// Seed global items catalog
+	seedGlobalItems(db);
 }

src/server/services/global-item.service.ts

@@ -0,0 +1,79 @@
+import { count, eq, like, or, sql } from "drizzle-orm";
+import { db as prodDb } from "../../db/index.ts";
+import { globalItems, itemGlobalLinks } from "../../db/schema.ts";
+
+type Db = typeof prodDb;
+
+/**
+ * Search global items by brand or model. SQLite LIKE is case-insensitive for ASCII.
+ * Escapes % and _ wildcard characters in user input.
+ */
+export function searchGlobalItems(db: Db = prodDb, query?: string) {
+	if (!query) {
+		return db.select().from(globalItems).all();
+	}
+
+	// Escape SQL LIKE wildcards
+	const escaped = query.replace(/%/g, "\\%").replace(/_/g, "\\_");
+	const pattern = `%${escaped}%`;
+
+	return db
+		.select()
+		.from(globalItems)
+		.where(
+			or(
+				like(globalItems.brand, pattern),
+				like(globalItems.model, pattern),
+			),
+		)
+		.all();
+}
+
+/**
+ * Get a single global item by ID with the count of user items linked to it.
+ */
+export function getGlobalItemWithOwnerCount(db: Db = prodDb, id: number) {
+	const item = db
+		.select()
+		.from(globalItems)
+		.where(eq(globalItems.id, id))
+		.get();
+
+	if (!item) return null;
+
+	const result = db
+		.select({ ownerCount: count() })
+		.from(itemGlobalLinks)
+		.where(eq(itemGlobalLinks.globalItemId, id))
+		.get();
+
+	return { ...item, ownerCount: result?.ownerCount ?? 0 };
+}
+
+/**
+ * Link a user's item to a global item. Throws on duplicate (unique constraint on itemId).
+ */
+export function linkItemToGlobal(
+	db: Db = prodDb,
+	itemId: number,
+	globalItemId: number,
+) {
+	return db
+		.insert(itemGlobalLinks)
+		.values({ itemId, globalItemId })
+		.returning()
+		.get();
+}
+
+/**
+ * Remove the link between a user's item and any global item.
+ */
+export function unlinkItemFromGlobal(db: Db = prodDb, itemId: number) {
+	const result = db
+		.delete(itemGlobalLinks)
+		.where(eq(itemGlobalLinks.itemId, itemId))
+		.returning()
+		.all();
+
+	return result.length;
+}