Enforce outbound↔return week coupling in Schedule filter (TZ §4.1.9.4)

- Tie return calendar minDate to outbound dateTo so earlier days grey
  out in the picker (Table 16: return cannot start before outbound ends;
  same week allowed).
- Auto-clear the return range when the user moves outbound forward and
  strands the previously-chosen return in an invalid state.
- Clearing outbound via the X button now cascades to the return range.

Rewrote two tests that previously asserted the submit-time error path;
the new proactive clearing makes that path unreachable for this case,
which is closer to the intent of the TZ.

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

@@ -305,7 +305,7 @@ describe("ScheduleFilter – validation per TZ §4.1.9.4", () => {
   // §4.1.9.4 return date must be >= outbound dateTo
   // -------------------------------------------------------------------------
 
-  it("4.1.9.4-R: return date before outbound dateTo shows error + blocks submit", () => {
+  it("4.1.9.4-R: return date before outbound dateTo auto-clears on mount (Table 16)", () => {
     render(
       <ScheduleFilter
         initialDeparture="SVO"
@@ -317,9 +317,11 @@ describe("ScheduleFilter – validation per TZ §4.1.9.4", () => {
         initialReturnDateTo="20260610"
       />,
     );
-    fireEvent.submit(screen.getByTestId("search-form"));
-    expect(screen.queryByTestId("schedule-return-before-outbound-error")).toBeTruthy();
-    expect(mockNavigate).not.toHaveBeenCalled();
+    // TZ §4.1.9.4 Table 16: an invalid retFrom < outTo combination is
+    // blanked before the user can even submit, rather than only raising
+    // an error after submit. The return X button is therefore hidden.
+    expect(screen.queryByTestId("schedule-return-date-clear")).toBeNull();
+    expect(screen.queryByTestId("schedule-return-before-outbound-error")).toBeNull();
   });
 
   it("4.1.9.4-R: return date equal to outbound dateTo passes validation", () => {
@@ -356,7 +358,7 @@ describe("ScheduleFilter – validation per TZ §4.1.9.4", () => {
     expect(mockNavigate).toHaveBeenCalled();
   });
 
-  it("4.1.9.4-R: return error clears after user clears the return date range", () => {
+  it("4.1.9.4-R: clearing outbound also clears return (Table 16 cascade)", () => {
     render(
       <ScheduleFilter
         initialDeparture="SVO"
@@ -364,17 +366,17 @@ describe("ScheduleFilter – validation per TZ §4.1.9.4", () => {
         initialDateFrom="20260601"
         initialDateTo="20260607"
         initialReturnFlights={true}
-        initialReturnDateFrom="20260603"
-        initialReturnDateTo="20260610"
+        initialReturnDateFrom="20260608"
+        initialReturnDateTo="20260614"
       />,
     );
-    fireEvent.submit(screen.getByTestId("search-form"));
-    expect(screen.queryByTestId("schedule-return-before-outbound-error")).toBeTruthy();
+    // Sanity: both ranges are populated.
+    expect(screen.queryByTestId("schedule-date-clear")).toBeTruthy();
+    expect(screen.queryByTestId("schedule-return-date-clear")).toBeTruthy();
 
-    const clearBtn = screen.queryByTestId("schedule-return-date-clear");
-    if (clearBtn) {
-      fireEvent.click(clearBtn);
-      expect(screen.queryByTestId("schedule-return-before-outbound-error")).toBeNull();
-    }
+    // Clicking the outbound X must clear both ranges.
+    fireEvent.click(screen.getByTestId("schedule-date-clear"));
+    expect(screen.queryByTestId("schedule-date-clear")).toBeNull();
+    expect(screen.queryByTestId("schedule-return-date-clear")).toBeNull();
   });
 });

src/features/schedule/components/ScheduleFilter.tsx

@@ -230,6 +230,27 @@ export const ScheduleFilter: FC<ScheduleFilterProps> = ({
     [submitLockedUntil, nowTs],
   );
 
+  // TZ §4.1.9.4 Table 16: when the outbound range moves forward such
+  // that the already-chosen return starts before the new outbound
+  // dateTo, blank the return picker and any coupled error so the user
+  // isn't left with an invalid combo. Intentionally does not fire when
+  // outbound is cleared — that's a separate "user actively cleared" flow
+  // handled on the outbound X button (see the clear handler below).
+  useEffect(() => {
+    if (!returnFlights) return;
+    const [, outTo] = dateRange;
+    const [retFrom] = returnDateRange;
+    if (!retFrom || !outTo) return;
+    const retFromDay = new Date(retFrom);
+    retFromDay.setHours(0, 0, 0, 0);
+    const outToDay = new Date(outTo);
+    outToDay.setHours(0, 0, 0, 0);
+    if (retFromDay.getTime() < outToDay.getTime()) {
+      setReturnDateRange([null, null]);
+      setReturnBeforeOutboundError(null);
+    }
+  }, [dateRange, returnFlights, returnDateRange]);
+
   // Swap the Calendar input's displayed text to "Текущая неделя" per
   // TZ §4.1.9 Table 14 when the selected range equals Mon-Sun of the
   // current week. Uses inputRef + useEffect to override PrimeReact's
@@ -452,8 +473,13 @@ export const ScheduleFilter: FC<ScheduleFilterProps> = ({
                     aria-label={t("SHARED.A11Y-CLEAR")}
                     data-testid="schedule-date-clear"
                     onClick={() => {
+                      // TZ §4.1.9.4 Table 16: clearing outbound also
+                      // clears return (return picker is only meaningful
+                      // relative to the outbound range).
                       setDateRange([null, null]);
                       setRangeError(null);
+                      setReturnDateRange([null, null]);
+                      setReturnBeforeOutboundError(null);
                     }}
                   >
                     &times;
@@ -543,7 +569,11 @@ export const ScheduleFilter: FC<ScheduleFilterProps> = ({
                         if (returnBeforeOutboundError) setReturnBeforeOutboundError(null);
                       }}
                       selectionMode="range"
-                      minDate={scheduleMinDate}
+                      // TZ §4.1.9.4: return cannot start before outbound's
+                      // dateTo. Tie the return picker's minDate to it so
+                      // earlier days grey out in the calendar UI. Same
+                      // week (retFrom = outTo) is allowed.
+                      minDate={dateRange[1] ?? scheduleMinDate}
                       maxDate={scheduleMaxDate}
                       disabledDates={returnDisabledDates}
                       dateFormat="dd.mm.yy"