V167 EXPORT LIKE IMPORT - ACCOUNT MIRROR - NO BACKUPS

- Import behavior is unchanged and remains account-isolated.
- Export Character is no longer grayed just because a bound id is not already cached in Lua.
- Export is available whenever an account is logged in and the record screen is in-game.
- On Export click, the router confirms that `characters` mirrors the active characters_<account> folder, exactly like Import preparation.
- If the selected character has no cached stable id yet, the router allocates the next account id (dra_1, kro_1, etc.) before opening Export.
- The native BG2 Export panel then opens with the filename locked to that one stable id.
- Re-exporting overwrites the same account character file; it does not create a second character export.
- Logout still deactivates the account flag and disconnects the account mirror.
- No automatic character backups or restoration are created.
