feat(frontend): race form, start time selects, calendar views, day page

- Hide org schedule fields when editing a past race; isRaceDateInPast helper
- StartTimeSelects (HH:mm:ss) and optional ?date= prefill on new race
- Full-card link to edit for races needing result entry; shadow token
- List/calendar toggle (sessionStorage); year grid and month focus views
- Date hover popover and /races/day/:ymd page with Add button
- Docs plan-korrektirovok-starty.md and startTime API note; client 0.4.0

Made-with: Cursor

frontend/src/pages/RaceDayPage.tsx

@@ -0,0 +1,133 @@
+import { useEffect, useMemo, useState } from "react";
+import { Link, useParams } from "react-router-dom";
+import type { Race } from "../api";
+import { ApiError, getRaces } from "../api";
+import { formatDistance, formatRaceDate, getRaceStatusClassName, getRaceStatusLabel, sortByDateAsc } from "../lib";
+
+function getErrorMessage(error: unknown): string {
+  if (error instanceof ApiError) {
+    return error.message;
+  }
+  return "Не удалось загрузить старты.";
+}
+
+export function RaceDayPage(): JSX.Element {
+  const { ymd } = useParams<{ ymd: string }>();
+  const [races, setRaces] = useState<Race[]>([]);
+  const [isLoading, setIsLoading] = useState(true);
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
+
+  const validYmd = ymd && /^\d{4}-\d{2}-\d{2}$/.test(ymd) ? ymd : null;
+  const year = validYmd ? parseInt(validYmd.slice(0, 4), 10) : NaN;
+
+  useEffect(() => {
+    if (!validYmd || Number.isNaN(year)) {
+      setIsLoading(false);
+      setRaces([]);
+      return;
+    }
+
+    const ac = new AbortController();
+    let mounted = true;
+
+    async function load(): Promise<void> {
+      setIsLoading(true);
+      try {
+        const items = await getRaces({ year }, { signal: ac.signal });
+        if (!mounted || ac.signal.aborted) {
+          return;
+        }
+        const forDay = items.filter((r) => r.date.slice(0, 10) === validYmd);
+        setRaces(sortByDateAsc(forDay));
+        setErrorMessage(null);
+      } catch (e) {
+        if (ac.signal.aborted || !mounted) {
+          return;
+        }
+        setErrorMessage(getErrorMessage(e));
+        setRaces([]);
+      } finally {
+        if (mounted && !ac.signal.aborted) {
+          setIsLoading(false);
+        }
+      }
+    }
+
+    void load();
+    return () => {
+      mounted = false;
+      ac.abort();
+    };
+  }, [validYmd, year]);
+
+  const heading = useMemo(() => {
+    if (!validYmd) {
+      return "Дата не указана";
+    }
+    return formatRaceDate(validYmd);
+  }, [validYmd]);
+
+  if (!validYmd) {
+    return (
+      <section className="page page--race-day">
+        <h1 className="page__title">Некорректная дата</h1>
+        <p className="page__subtitle">
+          <Link className="page-link" to="/races">
+            Вернуться к календарю стартов
+          </Link>
+        </p>
+      </section>
+    );
+  }
+
+  return (
+    <section className="page page--race-day">
+      <p className="page__subtitle">
+        <Link className="page-link" to="/races">
+          ← Календарь стартов
+        </Link>
+      </p>
+      <h1 className="page__title">{heading}</h1>
+
+      {errorMessage ? (
+        <p className="page__subtitle page__subtitle--error" role="alert">
+          {errorMessage}
+        </p>
+      ) : null}
+
+      {isLoading ? (
+        <p className="page__subtitle" aria-busy="true">
+          Загружаем…
+        </p>
+      ) : null}
+
+      {!isLoading && !errorMessage && races.length === 0 ? (
+        <p className="page__subtitle">На эту дату стартов нет.</p>
+      ) : null}
+
+      {!isLoading && races.length > 0 ? (
+        <ul className="race-day__list">
+          {races.map((race) => (
+            <li key={race.id} className="race-day__item">
+              <Link className="race-day__link" to={`/races/${race.id}`}>
+                {race.title}
+              </Link>
+              <span className="race-day__meta">
+                {formatDistance(race.distanceKm)} ·{" "}
+                <span className={getRaceStatusClassName(race.status, race.date)}>
+                  {getRaceStatusLabel(race.status, race.date)}
+                </span>
+              </span>
+            </li>
+          ))}
+        </ul>
+      ) : null}
+
+      <div className="race-day__actions">
+        <Link className="btn btn--primary" to={`/races/new?date=${validYmd}`}>
+          Добавить
+        </Link>
+      </div>
+    </section>
+  );
+}