V206 - ACTIVE ACCOUNT RELEASES ONLY ON BG2 EXIT

Base: V205.

Rules:
- Successful LOGIN keeps the existing per-account Flag=1 and Disabled=1 behavior.
- LOG OUT is disabled while an account is active.
- Calling drakAccountLogout() directly cannot clear the active account.
- Only BG2 EXIT/quit paths clear that same account to Flag=0 and Disabled=0.
- Other accounts are unaffected.
- V205 Import/Export selector behavior is unchanged.
- No automatic character backups or restoration.
