# Issue #180 Evidence — SPA next-round + final leaderboard

## Flow log (Angular SPA)
1. Host reaches `reveal` phase and runs `loadScoreboard()` (`GET /lobby/sessions/:code/scoreboard`).
2. Host can start next round directly in SPA via `startNextRound()` (`POST /lobby/sessions/:code/rounds/next`) and then session hydrate (`GET /lobby/sessions/:code`) without page reload.
3. Host can finish game directly in SPA via `finishGame()` (`POST /lobby/sessions/:code/finish`), rendering winner + sorted final leaderboard (plus raw payload for debug) in the same shell.
4. Player SPA renders final leaderboard from refreshed finished-session payload (sorted by score desc, nickname tiebreak) without leaving SPA route.
5. Error/retry paths are implemented and covered:
   - scoreboard failure -> `scoreboardError` + retry button
   - next-round failure -> `nextRoundError` + retry button
   - finish-game/final-leaderboard failure -> `finishError` + retry button

## Test evidence
### `frontend/angular` (Vitest)
- `src/app/features/host/host-shell.component.spec.ts`
  - `runs next-round transition without reload and clears scoreboard payload`
  - `captures finish-game failure for retry and stores final leaderboard on success`
- `src/app/features/player/player-shell.component.spec.ts`
  - `builds final leaderboard in finished status without legacy page hop`

Result:
- Test Files: 2 passed
- Tests: 9 passed

### `frontend` shared SPA tests (regression)
Result:
- Test Files: 5 passed
- Tests: 24 passed