chore: remove obsolete backup directories from March 2026

- Deleted backup_20260329_183359 (block height 2222, 3 accounts, 4 transactions)
- Deleted dependency_backup_20260331_204119 (pyproject.toml, requirements files)
- Deleted pre_deployment_20260402_120429 (config examples and environment templates)

backups/dependency_backup_20260331_204119/requirements-cli.txt

@@ -1,28 +0,0 @@
-# AITBC CLI Requirements
-# Specific dependencies for the AITBC CLI tool
-
-# Core CLI Dependencies
-requests>=2.32.0
-cryptography>=46.0.0
-pydantic>=2.12.0
-python-dotenv>=1.2.0
-
-# CLI Enhancement Dependencies
-click>=8.1.0
-rich>=13.0.0
-tabulate>=0.9.0
-colorama>=0.4.4
-keyring>=23.0.0
-click-completion>=0.5.2
-
-# JSON & Data Processing
-orjson>=3.10.0
-python-dateutil>=2.9.0
-pytz>=2024.1
-
-# Blockchain & Cryptocurrency
-base58>=2.1.1
-ecdsa>=0.19.0
-
-# Utilities
-psutil>=5.9.0