feat(ares): ARES company lookup with prefill in customer/supplier modals

New /api/admin/ares proxy (browser cannot reach ares.gov.cz - CORS+CSP):
GET /ico/:ico and GET /search?q= map the MFCR REST API to the form
shape (street incl. orientation numbers, "511 01" PSC format, DIC).
Guarded by customers.create/edit + warehouse.manage; token errors map
to Czech messages. Shared AresAdornment button sits in the Nazev and
ICO fields of both modals: ICO mode fills directly, name mode searches
with a result picker. Tested against live ARES (BOHA, ICO 22599851).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/__tests__/ares.test.ts

@@ -0,0 +1,116 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+import { aresLookupByIco, aresSearchByName } from "../services/ares.service";
+
+// ARES is a true external — mock global fetch (the only allowed mock class).
+const SUBJECT = {
+  ico: "22599851",
+  obchodniJmeno: "BOHA Automation s.r.o.",
+  dic: "CZ22599851",
+  sidlo: {
+    nazevStatu: "Česká republika",
+    nazevObce: "Turnov",
+    nazevCastiObce: "Turnov",
+    nazevUlice: "Nádražní",
+    cisloDomovni: 485,
+    psc: 51101,
+    textovaAdresa: "Nádražní 485, 51101 Turnov",
+  },
+};
+
+function mockFetchOnce(status: number, body?: unknown) {
+  return vi.spyOn(globalThis, "fetch").mockResolvedValueOnce({
+    ok: status >= 200 && status < 300,
+    status,
+    json: async () => body,
+  } as Response);
+}
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
+describe("aresLookupByIco", () => {
+  it("maps a subject to the normalized prefill shape", async () => {
+    mockFetchOnce(200, SUBJECT);
+    const res = await aresLookupByIco("22599851");
+    expect(res).toEqual({
+      ico: "22599851",
+      dic: "CZ22599851",
+      name: "BOHA Automation s.r.o.",
+      street: "Nádražní 485",
+      city: "Turnov",
+      postal_code: "511 01",
+      country: "Česká republika",
+    });
+  });
+
+  it("builds Prague-style orientation numbers as 'Ulice 485/12a'", async () => {
+    mockFetchOnce(200, {
+      ...SUBJECT,
+      sidlo: {
+        ...SUBJECT.sidlo,
+        cisloOrientacni: 12,
+        cisloOrientacniPismeno: "a",
+      },
+    });
+    const res = await aresLookupByIco("22599851");
+    expect("street" in res && res.street).toBe("Nádražní 485/12a");
+  });
+
+  it("rejects a non-8-digit IČO without calling ARES", async () => {
+    const spy = vi.spyOn(globalThis, "fetch");
+    expect(await aresLookupByIco("123")).toEqual({ error: "invalid_ico" });
+    expect(await aresLookupByIco("abcdefgh")).toEqual({
+      error: "invalid_ico",
+    });
+    expect(spy).not.toHaveBeenCalled();
+  });
+
+  it("accepts an IČO with stray whitespace", async () => {
+    const spy = mockFetchOnce(200, SUBJECT);
+    const res = await aresLookupByIco(" 225 99851 ");
+    expect("ico" in res && res.ico).toBe("22599851");
+    expect(String(spy.mock.calls[0][0])).toContain("/22599851");
+  });
+
+  it("maps 404 to not_found and network failure to ares_unavailable", async () => {
+    mockFetchOnce(404);
+    expect(await aresLookupByIco("12345678")).toEqual({ error: "not_found" });
+
+    vi.spyOn(globalThis, "fetch").mockRejectedValueOnce(new Error("ETIMEDOUT"));
+    expect(await aresLookupByIco("12345678")).toEqual({
+      error: "ares_unavailable",
+    });
+  });
+});
+
+describe("aresSearchByName", () => {
+  it("maps the result list and sends the name in the POST body", async () => {
+    const spy = mockFetchOnce(200, { ekonomickeSubjekty: [SUBJECT] });
+    const res = await aresSearchByName("BOHA Automation");
+    expect(Array.isArray(res)).toBe(true);
+    if (Array.isArray(res)) {
+      expect(res).toHaveLength(1);
+      expect(res[0].name).toBe("BOHA Automation s.r.o.");
+      expect(res[0].postal_code).toBe("511 01");
+    }
+    const init = spy.mock.calls[0][1] as RequestInit;
+    expect(JSON.parse(String(init.body))).toMatchObject({
+      obchodniJmeno: "BOHA Automation",
+      pocet: 10,
+    });
+  });
+
+  it("returns [] for a blank query without calling ARES", async () => {
+    const spy = vi.spyOn(globalThis, "fetch");
+    expect(await aresSearchByName("   ")).toEqual([]);
+    expect(spy).not.toHaveBeenCalled();
+  });
+
+  it("maps upstream failure to ares_unavailable", async () => {
+    mockFetchOnce(503);
+    expect(await aresSearchByName("BOHA")).toEqual({
+      error: "ares_unavailable",
+    });
+  });
+});