V126 SETUP INSTALLER FIX

- Corrected SETUP_IN_GAME_ACCOUNTS installer identity from V125 to V126.
- Installer now validates the V126-NATIVE-IMPORT-SAFE-STAGING runtime.
- Installer now validates SAVE ACCOUNT CHARACTER + IMPORT ACCOUNT CHARACTER.
- Preserves the V125-proven native SAVE behavior used successfully with multiple accounts.
- No backup, restore, copy, merge, synchronization, or respawn feature added.
