refactor: move cli/core/ to cli/aitbc_cli/core/ for proper package structure

- Moved core/ directory to aitbc_cli/core/ to make it a proper subpackage
- Updated aitbc_cli.py to load from new path
- Simplified aitbc_cli/__init__.py to use normal import instead of spec_from_file_location
- Updated all core imports to use aitbc_cli.core prefix
- Copied utils files (wallet_daemon_client, error_handling, crypto_utils, subprocess) to aitbc_cli/utils/
- Fixed wallet list command to work with new structure
- This fixes ModuleNotFoundError for aitbc_cli.core submodules

cli/utils/wallet_daemon_client.py

@@ -16,7 +16,7 @@ sys.path.insert(0, "/opt/aitbc/cli")
 from utils import error, success
 
 if TYPE_CHECKING:
-    from core.config import Config
+    from aitbc_cli.core.config import Config
 
 
 @dataclass