feat(18-02): add global item routes, item link/unlink endpoints, and route tests

- GET /api/global-items with optional q search parameter
- GET /api/global-items/:id with ownerCount
- POST /api/items/:id/link to link user item to global item
- DELETE /api/items/:id/link to unlink
- Route registered in index.ts
- 10 route tests covering all endpoints

tests/routes/global-items.test.ts

@@ -0,0 +1,181 @@
+import { beforeEach, describe, expect, it } from "bun:test";
+import { Hono } from "hono";
+import { globalItems, itemGlobalLinks, items } from "../../src/db/schema.ts";
+import { globalItemRoutes } from "../../src/server/routes/global-items.ts";
+import { itemRoutes } from "../../src/server/routes/items.ts";
+import { createTestDb } from "../helpers/db.ts";
+
+type TestDb = ReturnType<typeof createTestDb>;
+
+function createTestApp() {
+	const db = createTestDb();
+	const app = new Hono();
+
+	app.use("*", async (c, next) => {
+		c.set("db", db);
+		await next();
+	});
+
+	app.route("/api/global-items", globalItemRoutes);
+	app.route("/api/items", itemRoutes);
+	return { app, db };
+}
+
+function insertGlobalItem(db: TestDb, brand: string, model: string) {
+	return db
+		.insert(globalItems)
+		.values({ brand, model, category: "bags" })
+		.returning()
+		.get();
+}
+
+function insertItem(db: TestDb, name: string) {
+	return db
+		.insert(items)
+		.values({ name, categoryId: 1 })
+		.returning()
+		.get();
+}
+
+describe("Global Item Routes", () => {
+	let app: Hono;
+	let db: TestDb;
+
+	beforeEach(() => {
+		const testApp = createTestApp();
+		app = testApp.app;
+		db = testApp.db;
+	});
+
+	describe("GET /api/global-items", () => {
+		it("returns 200 with all global items", async () => {
+			insertGlobalItem(db, "Revelate Designs", "Terrapin System");
+			insertGlobalItem(db, "Apidura", "Handlebar Pack");
+
+			const res = await app.request("/api/global-items");
+			expect(res.status).toBe(200);
+
+			const body = await res.json();
+			expect(body).toHaveLength(2);
+		});
+
+		it("filters results by query parameter", async () => {
+			insertGlobalItem(db, "Revelate Designs", "Terrapin System");
+			insertGlobalItem(db, "Apidura", "Handlebar Pack");
+
+			const res = await app.request("/api/global-items?q=tent");
+			expect(res.status).toBe(200);
+
+			const body = await res.json();
+			// "tent" doesn't match "Terrapin" or "Handlebar" — expect 0
+			// Actually let's search for something that matches
+			const res2 = await app.request("/api/global-items?q=revelate");
+			const body2 = await res2.json();
+			expect(body2).toHaveLength(1);
+			expect(body2[0].brand).toBe("Revelate Designs");
+		});
+	});
+
+	describe("GET /api/global-items/:id", () => {
+		it("returns item with ownerCount", async () => {
+			const gi = insertGlobalItem(db, "MSR", "PocketRocket 2");
+
+			const res = await app.request(`/api/global-items/${gi.id}`);
+			expect(res.status).toBe(200);
+
+			const body = await res.json();
+			expect(body.brand).toBe("MSR");
+			expect(body.ownerCount).toBe(0);
+		});
+
+		it("returns 404 for non-existent id", async () => {
+			const res = await app.request("/api/global-items/999");
+			expect(res.status).toBe(404);
+		});
+
+		it("returns 400 for invalid id", async () => {
+			const res = await app.request("/api/global-items/abc");
+			expect(res.status).toBe(400);
+		});
+	});
+
+	describe("POST /api/items/:id/link", () => {
+		it("returns 201 when linking item to global item", async () => {
+			const gi = insertGlobalItem(db, "MSR", "PocketRocket 2");
+			const item = insertItem(db, "My Stove");
+
+			const res = await app.request(`/api/items/${item.id}/link`, {
+				method: "POST",
+				headers: { "Content-Type": "application/json" },
+				body: JSON.stringify({ globalItemId: gi.id }),
+			});
+
+			expect(res.status).toBe(201);
+			const body = await res.json();
+			expect(body.itemId).toBe(item.id);
+			expect(body.globalItemId).toBe(gi.id);
+		});
+
+		it("returns 409 when item already linked", async () => {
+			const gi = insertGlobalItem(db, "MSR", "PocketRocket 2");
+			const item = insertItem(db, "My Stove");
+
+			// Link once
+			await app.request(`/api/items/${item.id}/link`, {
+				method: "POST",
+				headers: { "Content-Type": "application/json" },
+				body: JSON.stringify({ globalItemId: gi.id }),
+			});
+
+			// Link again — should conflict
+			const res = await app.request(`/api/items/${item.id}/link`, {
+				method: "POST",
+				headers: { "Content-Type": "application/json" },
+				body: JSON.stringify({ globalItemId: gi.id }),
+			});
+
+			expect(res.status).toBe(409);
+		});
+
+		it("returns 404 when item does not exist", async () => {
+			const gi = insertGlobalItem(db, "MSR", "PocketRocket 2");
+
+			const res = await app.request("/api/items/999/link", {
+				method: "POST",
+				headers: { "Content-Type": "application/json" },
+				body: JSON.stringify({ globalItemId: gi.id }),
+			});
+
+			expect(res.status).toBe(404);
+		});
+	});
+
+	describe("DELETE /api/items/:id/link", () => {
+		it("returns 200 when unlinking", async () => {
+			const gi = insertGlobalItem(db, "MSR", "PocketRocket 2");
+			const item = insertItem(db, "My Stove");
+
+			// Link first
+			await app.request(`/api/items/${item.id}/link`, {
+				method: "POST",
+				headers: { "Content-Type": "application/json" },
+				body: JSON.stringify({ globalItemId: gi.id }),
+			});
+
+			// Unlink
+			const res = await app.request(`/api/items/${item.id}/link`, {
+				method: "DELETE",
+			});
+
+			expect(res.status).toBe(200);
+		});
+
+		it("returns 404 when item does not exist", async () => {
+			const res = await app.request("/api/items/999/link", {
+				method: "DELETE",
+			});
+
+			expect(res.status).toBe(404);
+		});
+	});
+});