Add championship hub with derived stats and progression views

New /api/v1/championship/hub endpoint aggregates official standings with
wins, podiums, poles, recent form, teammate head-to-head, and per-round
cumulative points. ChampionshipPage renders drivers, constructors, and
progression views.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/api.ts

@@ -1,4 +1,13 @@
-import type { ArticleContent, LiveStateResponse, Meeting, NewsItem, RaceHub, Session, Weekend } from './types'
+import type {
+  ArticleContent,
+  ChampionshipHub,
+  LiveStateResponse,
+  Meeting,
+  NewsItem,
+  RaceHub,
+  Session,
+  Weekend,
+} from './types'
 
 export async function fetchRaceHub(sessionKey: number): Promise<RaceHub> {
   const res = await fetch(`/api/v1/race-hub?session_key=${sessionKey}`)
@@ -52,6 +61,15 @@ export async function fetchWeekend(meetingKey: number): Promise<Weekend> {
   return res.json()
 }
 
+export async function fetchChampionshipHub(year?: number): Promise<ChampionshipHub> {
+  const url = year ? `/api/v1/championship/hub?year=${year}` : '/api/v1/championship/hub'
+  const res = await fetch(url)
+  if (!res.ok) {
+    throw new Error(`API ${res.status}: ${res.statusText}`)
+  }
+  return res.json()
+}
+
 export async function fetchLiveState(): Promise<LiveStateResponse> {
   const res = await fetch('/api/v1/live/state')
   if (!res.ok) {