Account-Rotation: Login/Premium-Badges + Live-Rotations-Panel + "Alle pruefen"

- Pro Mega-Debrid-Account UND Debrid-Link-Key im Bearbeiten-Dialog: Badge mit
  Login-Gueltigkeit + Premium-Restlaufzeit (connectUser vip_end / account/infos premiumLeft)
- "Alle pruefen"-Button oben rechts; prueft alle Accounts (Concurrency-Cap 4),
  Ergebnis persistiert (debridAccountStatuses), ueberlebt Neustart
- Rotations-Verlauf-Panel: zeigt live welcher Account/Key versucht wurde + warum
  gewechselt (Ring-Buffer -> Snapshot -> UI), statt nur "Link-Umwandlung erneut"
- Bug A: Mega-Debrid Per-Account-Verbrauch wurde nie erfasst (Heute/Insgesamt immer 0)
- Bug B: isProviderConfigured erkannte reine megaCredentials-Multi-Config nicht
- Neu: account-check.ts (standalone), CHECK_DEBRID_ACCOUNTS IPC, 13 Tests

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/renderer/styles.css

@@ -3138,3 +3138,43 @@ td {
     grid-column: span 1;
   }
 }
+
+
+/* ── Account validity + premium badges (account check) ───────────────── */
+.account-board-header-actions { display: flex; gap: 8px; align-items: center; }
+.account-validity-badge {
+  display: inline-block;
+  margin-top: 4px;
+  padding: 2px 8px;
+  border-radius: 999px;
+  font-size: 11px;
+  font-weight: 600;
+  letter-spacing: 0.2px;
+  border: 1px solid transparent;
+  white-space: nowrap;
+}
+.account-validity-badge.ok { color: #1c1206; background: linear-gradient(90deg, #7bd88f, #4fb96a); border-color: #4fb96a; }
+.account-validity-badge.free { color: #2a2113; background: #f2c14e; border-color: #d9a72f; }
+.account-validity-badge.invalid { color: #fff; background: #d9534f; border-color: #c0392b; }
+.account-validity-badge.unknown { color: var(--muted, #a59c8e); background: transparent; border-color: var(--line, #4a4032); }
+
+/* ── Live account-rotation panel ─────────────────────────────────────── */
+.rotation-panel { display: flex; flex-direction: column; gap: 6px; max-height: 320px; overflow-y: auto; }
+.rotation-empty { color: var(--muted, #a59c8e); font-size: 12px; }
+.rotation-event {
+  display: grid;
+  grid-template-columns: 72px 1fr;
+  gap: 8px;
+  align-items: baseline;
+  padding: 4px 8px;
+  border-radius: 6px;
+  font-size: 12px;
+  border-left: 3px solid var(--line, #4a4032);
+  background: rgba(255,255,255,0.02);
+}
+.rotation-event.WARN { border-left-color: #f2c14e; }
+.rotation-event.ERROR { border-left-color: #d9534f; }
+.rotation-event.INFO { border-left-color: #4fb96a; }
+.rotation-event .rotation-time { color: var(--muted, #a59c8e); font-variant-numeric: tabular-nums; }
+.rotation-event .rotation-body strong { font-weight: 600; }
+.rotation-event .rotation-reason { color: var(--muted, #a59c8e); }