feat(live): add web track map (#32)

Subscribe to SignalR Position.z and CarData.z, decode DEFLATE payloads, stream throttled positions over SSE, and render live car dots against cached track outline bounds with tap telemetry.

Alignment spike: no checked-in or locally cached real Position.z samples were available in this isolated worktree; verified both streams expose the official raw F1 X/Y/Z coordinate contract and implemented shared-bounds normalization against prefetched OpenF1 outlines. Fallback build-outline-from-stream was not taken.

Playwright remains out of scope for live rendering because BOXBOX_DISABLE_LIVE is used there; coverage is via parser, web handler/SSE, pure transform, and seeded component tests.

frontend/src/test/LiveComponents.test.tsx

@@ -7,9 +7,10 @@ import { BattleChips } from '../components/live/BattleChips'
 import { GapSparkline } from '../components/live/GapSparkline'
 import { PinnedDrivers } from '../components/live/PinnedDrivers'
 import { TimingTower } from '../components/live/TimingTower'
+import { TrackMap } from '../components/live/TrackMap'
 import { detectBattles } from '../lib/battles'
 import type { LiveTimingRow } from '../lib/live'
-import type { LiveDriverData, LiveWeatherData } from '../types'
+import type { LiveDriverData, LiveWeatherData, TrackOutline } from '../types'
 
 function makeRow(
   number: string,
@@ -241,3 +242,66 @@ describe('PinnedDrivers', () => {
     expect(screen.queryByTestId('pinned-strip')).not.toBeInTheDocument()
   })
 })
+
+describe('TrackMap', () => {
+  const outline: TrackOutline = {
+    circuit_key: 9,
+    bounds: { minX: 0, maxX: 100, minY: 0, maxY: 100 },
+    points: [
+      { x: 0, y: 0 },
+      { x: 1, y: 0 },
+      { x: 1, y: 1 },
+      { x: 0, y: 1 },
+    ],
+  }
+
+  it('renders car dots and opens mini telemetry on tap', () => {
+    render(
+      <TrackMap
+        outline={outline}
+        positions={{
+          '4': { x: 50, y: 25, z: 0, status: 'OnTrack' },
+          '81': { x: 25, y: 75, z: 0, status: 'OffTrack' },
+        }}
+        telemetry={{
+          '4': { Speed: 302, Throttle: 88, Brake: 0, DRS: 10, NGear: 8, RPM: 11111 },
+        }}
+        driverInfo={{
+          '4': {
+            RacingNumber: '4',
+            BroadcastName: 'L NORRIS',
+            Tla: 'NOR',
+            TeamName: 'McLaren',
+            TeamColour: 'ff8000',
+            FirstName: 'Lando',
+            LastName: 'Norris',
+          },
+          '81': {
+            RacingNumber: '81',
+            BroadcastName: 'O PIASTRI',
+            Tla: 'PIA',
+            TeamName: 'McLaren',
+            TeamColour: 'ff8000',
+            FirstName: 'Oscar',
+            LastName: 'Piastri',
+          },
+        }}
+      />,
+    )
+
+    expect(screen.getByTestId('track-map')).toHaveTextContent('2 cars')
+    fireEvent.click(screen.getByRole('button', { name: /NOR telemetry/i }))
+    const readout = screen.getByTestId('track-telemetry')
+    expect(readout).toHaveTextContent('NOR')
+    expect(readout).toHaveTextContent('302km/h')
+    expect(readout).toHaveTextContent('88%')
+    expect(readout).toHaveTextContent('DRS')
+    expect(readout).toHaveTextContent('10')
+    expect(screen.getByRole('button', { name: /PIA telemetry/i })).toHaveClass('track-car-inactive')
+  })
+
+  it('renders an empty state without outline data', () => {
+    render(<TrackMap outline={null} positions={{}} />)
+    expect(screen.getByTestId('track-map')).toHaveTextContent(/track outline unavailable/i)
+  })
+})

frontend/src/test/trackmap.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it } from 'vitest'
+import {
+  buildOutlinePath,
+  canvasToSvg,
+  isOnTrack,
+  normalizeRawPoint,
+  outlinePointToCanvas,
+} from '../lib/trackmap'
+
+describe('track map transforms', () => {
+  it('normalizes raw F1 coordinates into canvas space', () => {
+    const point = normalizeRawPoint(
+      { x: 50, y: 75 },
+      { minX: 0, maxX: 100, minY: 50, maxY: 100 },
+    )
+    expect(point).toEqual({ x: 0.5, y: 0.5 })
+    expect(canvasToSvg(point)).toEqual({ x: 50, y: 50 })
+  })
+
+  it('centers zero-range bounds and clamps out-of-range points', () => {
+    expect(normalizeRawPoint({ x: 10, y: 20 }, { minX: 10, maxX: 10, minY: 20, maxY: 20 }))
+      .toEqual({ x: 0.5, y: 0.5 })
+    expect(normalizeRawPoint({ x: 20, y: 5 }, { minX: 10, maxX: 15, minY: 10, maxY: 15 }))
+      .toEqual({ x: 1, y: 1 })
+  })
+
+  it('builds an SVG path from normalized outline points', () => {
+    expect(outlinePointToCanvas({ x: 0.25, y: 0.75 })).toEqual({ x: 0.25, y: 0.25 })
+    expect(buildOutlinePath([{ x: 0, y: 0 }, { x: 1, y: 1 }]))
+      .toBe('M 0.00 100.00 L 100.00 0.00')
+    expect(buildOutlinePath([{ x: 0, y: 0 }])).toBe('')
+  })
+
+  it('classifies on-track status defensively', () => {
+    expect(isOnTrack('OnTrack')).toBe(true)
+    expect(isOnTrack('OffTrack')).toBe(false)
+    expect(isOnTrack('')).toBe(true)
+  })
+})