V194 - V176 CHARACTERS + EXIT DEACTIVATION WATCHER

Base: V176 character/account import-export behavior.

Session changes only:
- Each account keeps its own '<ACCOUNTNAME> Activate' flag.
- Successful login remembers the account specifically for EXIT cleanup.
- LOG OUT clears only that account flag.
- Main UI EXIT clears only that account flag before BG2 exits.
- In-game quit/shutdown paths clear only that account flag.
- A local account_exit_watcher.py records which BG2 process logged into which account.
- If that BG2 process closes by EXIT, window X, or another process shutdown path, the watcher persists only that account's Activate=0 in Baldur.lua.
- Different BG2 windows/accounts remain independent.
- Setup clears stale Activate=1 values once while BG2 is closed.

Preserved from V176:
- Native character Import behavior.
- Native character Export behavior.
- Account character-folder routing.
- No automatic character backup or restoration.

The existing account_folder_router.py is byte-for-byte unchanged from the V176-preserved build.
