Fix popular-flight Search-button no-op when today is mid-week

User report: clicking a 'Расписание туда' popular tile on /onlineboard
filled the Schedule form but clicking Search did nothing.

Two bugs:
1. OnlineBoardStartPage's Schedule-bound popular-click handler wrote
   only { departure, arrival, withReturn } to the transient prefill —
   it skipped dateFrom/dateTo entirely. The Schedule calendar rendered
   empty, and on submit the form defaulted to today..today+7 (acceptable
   but TZ §4.1.5 mandates current-week prefill).
2. currentWeekBounds() returned the raw Monday of the ISO week. When
   today is mid-week (Tue-Sun), that Monday is N days in the past, so
   the Schedule route guard (§4.1.2, -1/+330 window) rejected the URL
   and silently redirected back to /schedule — user saw 'Search does
   nothing'.

Fix: populate dateFrom/dateTo (and returnDateFrom/returnDateTo for
RouteWithBack) in the Schedule prefill from both handlers, and clamp
the `from` end of currentWeekBounds() to max(Mon, today-1) so the
prefilled range is always inside the window. nextWeekBounds now derives
from the raw Monday (not the clamped `from`) so next-week is always
the true next ISO week.

Live retest: popular 'Москва — Мурманск' → Schedule prefilled with
cities + '21.04.2026 - 26.04.2026' → Search navigates to
/schedule/route/MOW-MMK-20260421-20260426. 0 console errors.
2044 tests pass, typecheck clean.

src/features/online-board/components/OnlineBoardStartPage.tsx

@@ -83,6 +83,57 @@ function todayYyyymmdd(): string {
   return `${y}${m}${day}`;
 }
 
+function dateToYyyymmdd(value: Date): string {
+  const y = value.getFullYear().toString();
+  const m = (value.getMonth() + 1).toString().padStart(2, "0");
+  const d = value.getDate().toString().padStart(2, "0");
+  return `${y}${m}${d}`;
+}
+
+/**
+ * Mon-Sun bounds of the ISO week containing `base` (or today), CLAMPED to
+ * the Schedule date window's lower edge (today - 1). When today falls mid-week,
+ * returning a Monday that is already past the -1-day window would make the
+ * subsequent route guard redirect back to the start page, so we clamp the
+ * `from` end to max(mon, today - 1). Used by TZ §4.1.5 Schedule popular-click
+ * prefill — "показать расписание на = текущая неделя".
+ */
+function currentWeekBoundsYyyymmdd(base = new Date()): { from: string; to: string } {
+  const d = new Date(base);
+  d.setHours(0, 0, 0, 0);
+  const dow = d.getDay() === 0 ? 7 : d.getDay();
+  const mon = new Date(d);
+  mon.setDate(d.getDate() - (dow - 1));
+  const sun = new Date(mon);
+  sun.setDate(mon.getDate() + 6);
+  // Clamp `from` to today − 1 so the prefilled range is always inside
+  // Schedule's [−1, +330] window and the route guard never rejects it.
+  const minFrom = new Date(d);
+  minFrom.setDate(d.getDate() - 1);
+  const from = mon.getTime() < minFrom.getTime() ? minFrom : mon;
+  return { from: dateToYyyymmdd(from), to: dateToYyyymmdd(sun) };
+}
+
+/**
+ * Mon–Sun bounds of the ISO week AFTER the one containing `base`.
+ * Used by TZ §4.1.5 round-trip prefill — "дата обратного рейса = следующая неделя".
+ * Derived from the raw Monday of the current week (not the clamped
+ * `currentWeekBoundsYyyymmdd().from`) so the next-Mon is always correct
+ * regardless of how mid-week `base` is.
+ */
+function nextWeekBoundsYyyymmdd(base = new Date()): { from: string; to: string } {
+  const d = new Date(base);
+  d.setHours(0, 0, 0, 0);
+  const dow = d.getDay() === 0 ? 7 : d.getDay();
+  const thisMon = new Date(d);
+  thisMon.setDate(d.getDate() - (dow - 1));
+  const nextMon = new Date(thisMon);
+  nextMon.setDate(thisMon.getDate() + 7);
+  const nextSun = new Date(nextMon);
+  nextSun.setDate(nextMon.getDate() + 6);
+  return { from: dateToYyyymmdd(nextMon), to: dateToYyyymmdd(nextSun) };
+}
+
 export function buildOnlineBoardPrefillState(
   request: PopularRequest,
   dictionaries: IDictionaries | null = null,
@@ -192,13 +243,28 @@ export const OnlineBoardStartPage: FC = () => {
       // so the destination form pre-fills with a city rather than an
       // airport pin.
       if (request.type === "Schedule") {
-        const state =
+        // TZ §4.1.5: Schedule-bound popular clicks prefill the date range
+        // to the current ISO week (Mon-Sun); round-trip additionally sets
+        // the return range to the following ISO week. Without these the
+        // Schedule calendar renders empty until submit.
+        const state: Record<string, unknown> =
           request.mode === "Route" || request.mode === "RouteWithBack"
-            ? {
-                departure: toCityCode(request.departure, dictionaries),
-                arrival: toCityCode(request.arrival, dictionaries),
-                withReturn: request.mode === "RouteWithBack",
-              }
+            ? (() => {
+                const base: Record<string, unknown> = {
+                  departure: toCityCode(request.departure, dictionaries),
+                  arrival: toCityCode(request.arrival, dictionaries),
+                  withReturn: request.mode === "RouteWithBack",
+                };
+                const cur = currentWeekBoundsYyyymmdd();
+                base.dateFrom = cur.from;
+                base.dateTo = cur.to;
+                if (request.mode === "RouteWithBack") {
+                  const nxt = nextWeekBoundsYyyymmdd();
+                  base.returnDateFrom = nxt.from;
+                  base.returnDateTo = nxt.to;
+                }
+                return base;
+              })()
             : {};
         writeTransientPrefill(SCHEDULE_PREFILL_SLOT, state);
         navigate(`/${locale}/schedule`);

src/features/schedule/components/ScheduleStartPage.test.tsx

@@ -187,28 +187,31 @@ describe("ScheduleStartPage", () => {
     });
   });
 
-  it("4.1.5-S1: one-way Route click prefills current ISO week dates + no return", () => {
-    // 2026-05-15 (Fri) → week Mon 2026-05-11 … Sun 2026-05-17
+  it("4.1.5-S1: one-way Route click prefills current ISO week dates (from clamped to today-1) + no return", () => {
+    // 2026-05-15 (Fri) → raw Mon 2026-05-11, raw Sun 2026-05-17
+    // `from` is clamped to today−1 = 2026-05-14 so the route guard does
+    // not redirect the search back to the start page.
     render(<ScheduleStartPage />);
     fireEvent.click(screen.getByTestId("popular-click-route"));
     const stored = JSON.parse(sessionStore.getRaw("afl-prefill:schedule")!);
     expect(stored.departure).toBe("SVO");
     expect(stored.arrival).toBe("LED");
     expect(stored.withReturn).toBe(false);
-    expect(stored.dateFrom).toBe("20260511"); // Mon
+    expect(stored.dateFrom).toBe("20260514"); // clamped to today−1 (raw Mon was 2026-05-11)
     expect(stored.dateTo).toBe("20260517");   // Sun
     expect(stored.returnDateFrom).toBeUndefined();
     expect(stored.returnDateTo).toBeUndefined();
     expect(mockNavigate).toHaveBeenCalledWith("/ru-ru/schedule");
   });
 
-  it("4.1.5-S2: round-trip RouteWithBack click prefills current + next week dates", () => {
-    // current week: 20260511-20260517; next week: 20260518-20260524
+  it("4.1.5-S2: round-trip RouteWithBack click prefills current + next week dates (outbound from clamped)", () => {
+    // current week raw: 20260511-20260517 (clamped from: 20260514-20260517)
+    // next week: 20260518-20260524 (unclamped — future)
     render(<ScheduleStartPage />);
     fireEvent.click(screen.getByTestId("popular-click-roundtrip"));
     const stored = JSON.parse(sessionStore.getRaw("afl-prefill:schedule")!);
     expect(stored.withReturn).toBe(true);
-    expect(stored.dateFrom).toBe("20260511");
+    expect(stored.dateFrom).toBe("20260514"); // clamped
     expect(stored.dateTo).toBe("20260517");
     expect(stored.returnDateFrom).toBe("20260518"); // next Mon
     expect(stored.returnDateTo).toBe("20260524");   // next Sun
@@ -288,8 +291,9 @@ describe("4.1.9-R: Current-Week label substitution", () => {
     render(<ScheduleStartPage />);
     fireEvent.click(screen.getByTestId("popular-click-route"));
     const stored = JSON.parse(sessionStore.getRaw("afl-prefill:schedule")!);
-    // Current week Mon-Sun for 2026-05-15
-    expect(stored.dateFrom).toBe("20260511");
+    // Current week Sun for 2026-05-15 is 2026-05-17; `from` is clamped to
+    // today−1 = 2026-05-14 so the range is inside Schedule's −1/+330 window.
+    expect(stored.dateFrom).toBe("20260514");
     expect(stored.dateTo).toBe("20260517");
   });
 });

src/features/schedule/components/ScheduleStartPage.tsx

@@ -76,8 +76,12 @@ function yyyymmddToDate(yyyymmdd: string): Date {
 }
 
 /**
- * Returns Mon–Sun bounds of the ISO week containing `base` (or today).
- * TZ §4.1.5: "показать расписание на = текущая неделя".
+ * Returns Mon–Sun bounds of the ISO week containing `base` (or today),
+ * clamped to today − 1 on the `from` end so the range is always inside
+ * Schedule's [−1, +330] date window. TZ §4.1.5 says "показать расписание
+ * на = текущая неделя"; when today falls mid-week the unclamped Monday
+ * would be past the window's lower edge and the route guard would redirect
+ * the search back to the start page.
  */
 function currentWeekBounds(base = new Date()): { from: Date; to: Date } {
   const d = new Date(base);
@@ -88,17 +92,28 @@ function currentWeekBounds(base = new Date()): { from: Date; to: Date } {
   mon.setDate(d.getDate() - (dow - 1));
   const sun = new Date(mon);
   sun.setDate(mon.getDate() + 6);
-  return { from: mon, to: sun };
+  const minFrom = new Date(d);
+  minFrom.setDate(d.getDate() - 1);
+  const from = mon.getTime() < minFrom.getTime() ? minFrom : mon;
+  return { from, to: sun };
 }
 
 /**
  * Returns Mon–Sun bounds of the week *after* the ISO week containing `base`.
  * TZ §4.1.5: "дата обратного рейса = следующая неделя".
+ *
+ * Derived from the raw Monday of `base`'s ISO week (not the clamped
+ * `currentWeekBounds().from`) so the return-leg always starts on the true
+ * next Monday regardless of how mid-week `base` is.
  */
 function nextWeekBounds(base = new Date()): { from: Date; to: Date } {
-  const cur = currentWeekBounds(base);
-  const nextMon = new Date(cur.from);
-  nextMon.setDate(cur.from.getDate() + 7);
+  const d = new Date(base);
+  d.setHours(0, 0, 0, 0);
+  const dow = d.getDay() === 0 ? 7 : d.getDay();
+  const thisMon = new Date(d);
+  thisMon.setDate(d.getDate() - (dow - 1));
+  const nextMon = new Date(thisMon);
+  nextMon.setDate(thisMon.getDate() + 7);
   const nextSun = new Date(nextMon);
   nextSun.setDate(nextMon.getDate() + 6);
   return { from: nextMon, to: nextSun };