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/pre_deployment_20260402_120838/config/networks/chain_enhanced_devnet.yaml

@@ -1,30 +0,0 @@
-chain_id: "aitbc-enhanced-devnet"
-chain_type: "topic"
-purpose: "development-with-new-features"
-name: "AITBC Enhanced Devnet"
-description: "Enhanced development network with AI trading, surveillance, analytics, and multi-chain features"
-consensus:
-  algorithm: "poa"
-  authorities:
-    - "ait1devproposer000000000000000000000000000000"
-    - "ait1aivalidator00000000000000000000000000000"
-    - "ait1surveillance0000000000000000000000000000"
-  block_time: 3
-  max_validators: 100
-parameters:
-  block_reward: "2000000000000000000"
-  max_block_size: 2097152
-  max_gas_per_block: 15000000
-  min_gas_price: 1000000000
-  min_stake: 1000
-features:
-  ai_trading_engine: true
-  ai_surveillance: true
-  advanced_analytics: true
-  enterprise_integration: true
-  multi_modal_ai: true
-  zk_proofs: true
-  cross_chain_bridge: true
-  global_marketplace: true
-  adaptive_learning: true
-  performance_monitoring: true