Fix schedule search endpoint (GET not POST, dateTo + 1 day)

Angular's ScheduleApiService.getFlights uses GET with query params
and a half-open date interval (sends dateTo = requested end + 1 day).
React sent POST with a JSON body matching the params verbatim, which
returned HTTP 500 from the backend.

searchSchedule now:
- GETs flights/1/{lang}/schedule with ?departure=...&arrival=...
- extends dateTo by one day
- coerces connections to '0'/'1' and drops empty timeFrom/timeTo

Verified the call returns 200 with real flight data for
SVO→LED 2026-04-18..2026-04-25. Updated the api tests accordingly.

src/features/schedule/api.test.ts

@@ -69,7 +69,7 @@ const DAYS_RESPONSE: IScheduleDaysResponse = {
 // ---------------------------------------------------------------------------
 
 describe("searchSchedule", () => {
-  it("sends POST to schedule/1", async () => {
+  it("sends GET to schedule/1 with query params", async () => {
     const { client, mockFetch } = createMockClient(SCHEDULE_RESPONSE);
 
     const params: IScheduleSearchRequest = {
@@ -83,10 +83,10 @@ describe("searchSchedule", () => {
 
     const url = extractUrl(mockFetch);
     expect(url.pathname).toBe("/flights/1/ru/schedule");
-    expect(extractMethod(mockFetch)).toBe("POST");
+    expect(extractMethod(mockFetch)).toBe("GET");
   });
 
-  it("sends params as JSON body", async () => {
+  it("advances dateTo by 1 day (half-open interval)", async () => {
     const { client, mockFetch } = createMockClient(SCHEDULE_RESPONSE);
 
     const params: IScheduleSearchRequest = {
@@ -99,8 +99,12 @@ describe("searchSchedule", () => {
 
     await searchSchedule(client, params);
 
-    const body = extractBody(mockFetch);
-    expect(body).toEqual(params);
+    const url = extractUrl(mockFetch);
+    expect(url.searchParams.get("departure")).toBe("SVO");
+    expect(url.searchParams.get("arrival")).toBe("LED");
+    expect(url.searchParams.get("dateFrom")).toBe("2025-01-15");
+    expect(url.searchParams.get("dateTo")).toBe("2025-01-17");
+    expect(url.searchParams.get("connections")).toBe("1");
   });
 
   it("returns the deserialized response", async () => {

src/features/schedule/api.ts

@@ -22,15 +22,45 @@ import type {
 
 /**
  * Search schedule flights.
- * Maps to: `POST schedule/1` with body parameters.
+ * Maps to: `GET schedule/1?departure=SVO&arrival=LED&dateFrom=2026-04-18&dateTo=2026-04-26&...`
  *
- * The API response is an array of flight objects (IFlight[]).
+ * Mirrors Angular's ScheduleApiService.getFlights which:
+ *  - uses GET with query params (not POST with JSON body)
+ *  - sends dateTo = requested end + 1 day (half-open interval)
+ *  - coerces `connections` to a string ('0' / '1')
+ *  - drops empty timeFrom/timeTo
  */
 export async function searchSchedule(
   client: ApiClient,
   params: IScheduleSearchRequest,
 ): Promise<IScheduleResponse> {
-  return client.post<IScheduleResponse>(`flights/1/${client.locale}/schedule`, params);
+  const query: Record<string, string> = {
+    departure: params.departure,
+    arrival: params.arrival,
+    dateFrom: params.dateFrom,
+    dateTo: addOneDayIso(params.dateTo),
+    connections: String(params.connections ?? 1),
+  };
+  if (params.timeFrom) query["timeFrom"] = params.timeFrom;
+  if (params.timeTo) query["timeTo"] = params.timeTo;
+  if (params.attribute) query["attribute"] = String(params.attribute);
+  return client.get<IScheduleResponse>(
+    `flights/1/${client.locale}/schedule`,
+    query,
+  );
+}
+
+/** Return the date one day after a yyyy-MM-dd string (passthrough on bad input). */
+function addOneDayIso(iso: string): string {
+  const m = /^(\d{4})-(\d{2})-(\d{2})(.*)$/.exec(iso);
+  if (!m) return iso;
+  const [, y, mm, dd, tail] = m;
+  const d = new Date(Number(y), Number(mm) - 1, Number(dd));
+  d.setDate(d.getDate() + 1);
+  const ny = d.getFullYear().toString();
+  const nm = (d.getMonth() + 1).toString().padStart(2, "0");
+  const nd = d.getDate().toString().padStart(2, "0");
+  return `${ny}-${nm}-${nd}${tail ?? ""}`;
 }
 
 /**