feat: CRUD UI — race form, detail fields, edit/delete actions

- RaceDetailsPage: show all non-null fields (officialUrl, startTime, clusterSchedule, bibPickup)

- RaceDetailsPage: add edit link and delete button with confirmation banner

- RaceFormPage: universal create/edit form with validation, auto-generated id for new races

- Router: add /races/new and /races/:raceId/edit routes

- AppLayout: add navigation link to create new race

- CSS: buttons (primary/secondary/danger), form fields, confirm banner, responsive layout

Made-with: Cursor

frontend/src/pages/RaceDetailsPage.tsx

@@ -1,6 +1,6 @@
-import { useEffect, useMemo, useState } from "react";
-import { Link, useParams } from "react-router-dom";
-import { ApiError, getRaceById } from "../api";
+import { useCallback, useEffect, useMemo, useState } from "react";
+import { Link, useNavigate, useParams } from "react-router-dom";
+import { ApiError, deleteRace, getRaceById } from "../api";
 import {
   formatDistance,
   formatRaceDate,
@@ -17,11 +17,44 @@ function getErrorMessage(error: unknown): string {
   return "Не удалось загрузить карточку старта.";
 }
 
+function DetailItem(props: { label: string; value: string | null | undefined }): JSX.Element | null {
+  const text = props.value?.trim();
+  if (!text) {
+    return null;
+  }
+  return (
+    <div className="race-details-meta__item">
+      <dt className="race-details-meta__key">{props.label}</dt>
+      <dd className="race-details-meta__value">{text}</dd>
+    </div>
+  );
+}
+
+function DetailLink(props: { label: string; url: string | null | undefined }): JSX.Element | null {
+  const href = props.url?.trim();
+  if (!href) {
+    return null;
+  }
+  return (
+    <div className="race-details-meta__item">
+      <dt className="race-details-meta__key">{props.label}</dt>
+      <dd className="race-details-meta__value">
+        <a href={href} target="_blank" rel="noopener noreferrer" className="race-details-meta__link">
+          {href}
+        </a>
+      </dd>
+    </div>
+  );
+}
+
 export function RaceDetailsPage(): JSX.Element {
   const { raceId } = useParams<{ raceId: string }>();
+  const navigate = useNavigate();
   const [race, setRace] = useState<Race | null>(null);
   const [isLoading, setIsLoading] = useState<boolean>(true);
   const [errorMessage, setErrorMessage] = useState<string | null>(null);
+  const [isDeleting, setIsDeleting] = useState<boolean>(false);
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState<boolean>(false);
 
   useEffect(() => {
     let isMounted = true;
@@ -65,6 +98,22 @@ export function RaceDetailsPage(): JSX.Element {
     return getPaceLabel(race.finishTime, race.distanceKm);
   }, [race]);
 
+  const handleDelete = useCallback(async () => {
+    if (!raceId) {
+      return;
+    }
+    setIsDeleting(true);
+    try {
+      await deleteRace(raceId);
+      navigate("/races", { replace: true });
+    } catch (error) {
+      setErrorMessage(error instanceof ApiError ? error.message : "Не удалось удалить старт.");
+      setShowDeleteConfirm(false);
+    } finally {
+      setIsDeleting(false);
+    }
+  }, [raceId, navigate]);
+
   if (isLoading) {
     return (
       <section className="page page--race-details" aria-busy="true">
@@ -100,6 +149,43 @@ export function RaceDetailsPage(): JSX.Element {
         <span className={getRaceStatusClassName(race.status)}>{getRaceStatusLabel(race.status)}</span>
       </div>
 
+      <div className="race-details-actions">
+        <Link className="btn btn--primary" to={`/races/${race.id}/edit`}>
+          Редактировать
+        </Link>
+        <button
+          className="btn btn--danger"
+          type="button"
+          onClick={() => setShowDeleteConfirm(true)}
+        >
+          Удалить
+        </button>
+      </div>
+
+      {showDeleteConfirm ? (
+        <div className="confirm-banner" role="alertdialog" aria-label="Подтверждение удаления">
+          <p className="confirm-banner__text">Удалить «{race.title}»? Это действие необратимо.</p>
+          <div className="confirm-banner__actions">
+            <button
+              className="btn btn--danger"
+              type="button"
+              disabled={isDeleting}
+              onClick={handleDelete}
+            >
+              {isDeleting ? "Удаляем…" : "Да, удалить"}
+            </button>
+            <button
+              className="btn btn--secondary"
+              type="button"
+              disabled={isDeleting}
+              onClick={() => setShowDeleteConfirm(false)}
+            >
+              Отмена
+            </button>
+          </div>
+        </div>
+      ) : null}
+
       <div className="race-details-grid">
         <article className="race-details-card">
           <h2 className="race-details-card__title">Основная информация</h2>
@@ -116,11 +202,16 @@ export function RaceDetailsPage(): JSX.Element {
               <dt className="race-details-meta__key">Статус</dt>
               <dd className="race-details-meta__value">{getRaceStatusLabel(race.status)}</dd>
             </div>
+            <DetailLink label="Сайт организатора" url={race.officialUrl} />
+            <DetailItem label="Время старта" value={race.startTime} />
+            <DetailItem label="Расписание кластеров" value={race.clusterSchedule} />
+            <DetailItem label="Выдача номеров" value={race.bibPickup} />
+            <DetailItem label="Стартовый номер" value={race.bibNumber} />
           </dl>
         </article>
 
         <article className="race-details-card">
-          <h2 className="race-details-card__title">Completed-метрики</h2>
+          <h2 className="race-details-card__title">Результаты</h2>
           {isCompleted ? (
             <dl className="race-details-meta">
               <div className="race-details-meta__item">
@@ -131,16 +222,7 @@ export function RaceDetailsPage(): JSX.Element {
                 <dt className="race-details-meta__key">Темп</dt>
                 <dd className="race-details-meta__value">{paceLabel ?? "не удалось вычислить"}</dd>
               </div>
-              <div className="race-details-meta__item">
-                <dt className="race-details-meta__key">Место</dt>
-                <dd className="race-details-meta__value">
-                  {race.finishPlace?.trim() ? race.finishPlace : "не указано"}
-                </dd>
-              </div>
-              <div className="race-details-meta__item">
-                <dt className="race-details-meta__key">Стартовый номер</dt>
-                <dd className="race-details-meta__value">{race.bibNumber ?? "не указан"}</dd>
-              </div>
+              <DetailItem label="Место" value={race.finishPlace} />
             </dl>
           ) : (
             <p className="race-details-card__empty">