feat: align docs with code, finish_place, registered status, UI filters, tests, CI

- Add PLAN.md and sync backend docs, .env.example, API doc (404 details)
- Document mock DB and PORT/API_PORT in docs/backend.md; README monorepo + frontend/.env.example
- Migration 002: finish_place column, status registered; mapper and mock DB updated
- Frontend: registered status, finishPlace, calendar year/month filters, pace sparkline
- Extract createApp for tests; supertest + tsx; GitHub Actions CI

Made-with: Cursor

frontend/src/pages/DashboardPage.tsx

@@ -1,11 +1,13 @@
 import { useEffect, useMemo, useState } from "react";
 import type { Race } from "../api";
 import { ApiError, getRaces } from "../api";
+import { PaceTrendChart } from "../components";
 import {
   formatDistance,
   formatRaceDate,
   getRaceCountdownLabel,
   getPaceLabel,
+  isCloseDistance,
   parseFinishTimeToSeconds,
   splitRacesByDate,
 } from "../lib";
@@ -19,14 +21,11 @@ function getErrorMessage(error: unknown): string {
   return "Не удалось загрузить данные dashboard.";
 }
 
-function isSameDistance(left: number, right: number): boolean {
-  return Math.abs(left - right) < 0.05;
-}
-
 export function DashboardPage(): JSX.Element {
   const [races, setRaces] = useState<Race[]>([]);
   const [isLoading, setIsLoading] = useState<boolean>(true);
   const [errorMessage, setErrorMessage] = useState<string | null>(null);
+  const [chartDistanceKm, setChartDistanceKm] = useState<number>(10);
 
   useEffect(() => {
     let isMounted = true;
@@ -98,7 +97,7 @@ export function DashboardPage(): JSX.Element {
       const candidates = races.filter((race) => {
         return (
           race.status === "completed" &&
-          isSameDistance(race.distanceKm, distanceKm) &&
+          isCloseDistance(race.distanceKm, distanceKm) &&
           Boolean(parseFinishTimeToSeconds(race.finishTime))
         );
       });
@@ -136,7 +135,7 @@ export function DashboardPage(): JSX.Element {
         distance: formatDistance(race.distanceKm),
         finishTime: race.finishTime ?? "время не указано",
         pace: getPaceLabel(race.finishTime, race.distanceKm) ?? "не удалось вычислить",
-        place: "нет данных",
+        place: race.finishPlace?.trim() ? race.finishPlace : "нет данных",
       }))
       .sort((left, right) => right.year - left.year || left.title.localeCompare(right.title, "ru-RU"));
   }, [races]);
@@ -218,6 +217,30 @@ export function DashboardPage(): JSX.Element {
         </article>
       </div>
 
+      <section className="dashboard-section" aria-label="Динамика времени на дистанции">
+        <h2 className="dashboard-section__title">Прогресс по времени</h2>
+        <p className="dashboard-section__intro">
+          Линия по завершённым стартам выбранной дистанции: выше — лучше время (короче гонка).
+        </p>
+        <label className="races-filter__field">
+          <span className="races-filter__label">Дистанция для графика</span>
+          <select
+            className="races-filter__select"
+            value={String(chartDistanceKm)}
+            onChange={(event) => {
+              setChartDistanceKm(Number(event.target.value));
+            }}
+          >
+            {PR_DISTANCES.map((d) => (
+              <option key={d} value={d}>
+                {formatDistance(d)}
+              </option>
+            ))}
+          </select>
+        </label>
+        <PaceTrendChart races={races} distanceKm={chartDistanceKm} />
+      </section>
+
       <section className="dashboard-section" aria-label="Личные рекорды по дистанциям">
         <h2 className="dashboard-section__title">PR по дистанциям</h2>
         <div className="dashboard-grid dashboard-grid--pr">