V127 - NATIVE BG2 IMPORT AFTER ACCOUNT STAGING / NO BACKUPS

SAVE ACCOUNT CHARACTER:
- Keeps the V125-proven behavior: BG2 exports normally to `characters`, then only that newly exported CHR/BIO pair is physically moved to characters_<account>.

IMPORT ACCOUNT CHARACTER:
- Moves the logged-in account CHR/BIO files from characters_<account> into BG2's literal `characters` folder.
- Opens BG2's normal native Import Character list.
- The Import screen's Done and Back buttons are BG2's stock actions; no custom file-mover action runs when either is pressed.
- Staged account files remain in `characters` while BG2 needs them. They are returned to characters_<account> later at a safe account action such as SAVE, LOG OUT, the next account import, or router restart.

This intentionally favors the native BG2 import path because moving the CHR/BIO during import completion caused crashes.
No character copies, backups, restore history, synchronization, or respawning.
