settings: move Player/transcode and Account into their own tabs

The "Система" tab was a catch-all (Recording, Player & transcoding,
Storage, System info, Account). Split out two dedicated tabs:

- "Плеер": per-browser playback/transcode profiles. Kept at operator+
  (the transcode option spawns server-side ffmpeg, i.e. CPU load).
- "Учётная запись": current user + logout. Ungated, so any signed-in
  user (incl. viewers) can log out -- previously it was buried inside
  the operator-only "Система" tab.

.tabs gets flex-wrap so the now-7 tabs wrap instead of overflowing.
VERSION -> 0.0.117.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/static/style.css

@@ -328,7 +328,7 @@ input[type="date"], select {
 .settings-main .wrap { max-width: 920px; margin: 0 auto; }
 
 /* Вкладки (как в браузере) */
-.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--border); margin-bottom: 18px; }
+.tabs { display: flex; flex-wrap: wrap; gap: 4px; border-bottom: 1px solid var(--border); margin-bottom: 18px; }
 .tab {
   background: none; border: none; border-bottom: 2px solid transparent; border-radius: 0;
   color: var(--text-dim); padding: 10px 18px; cursor: pointer; font-size: 14px; font-weight: 500;