fix(soak): multi-hole round transitions, token refresh, dashboard wiring

- Session loop now handles round_over by clicking #ss-next-btn (the
  scoresheet modal button) instead of exiting early. Waits for next
  round or game_over before continuing.
- SessionPool detects expired tokens on acquire and re-logins
  automatically, writing fresh credentials to .env.stresstest.
- Added 2s post-game delay before goto('/') so the server can process
  game completion before WebSocket disconnect.
- Wired dashboard metrics (games_completed, moves_total, errors),
  activity log entries, and player tiles for both populate and stress
  scenarios.
- Bumped screencast resolution to 960x540 and set headless viewport
  to 960x800 for better click-to-watch framing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/soak/dashboard/dashboard.css

@@ -167,7 +167,9 @@ body {
 }
 #video-frame {
   display: block;
+  width: 960px;
   max-width: 100%;
-  max-height: 70vh;
+  max-height: 80vh;
+  object-fit: contain;
   border: 1px solid var(--border);
 }