refactor: consolidate blockchain explorer into single app and update backup ignore patterns

- Remove standalone explorer-web app (README, HTML, package files)
- Add /web endpoint to blockchain-explorer for web interface access
- Update .gitignore to exclude application backup archives (*.tar.gz, *.zip)
- Add backup documentation files to .gitignore (BACKUP_INDEX.md, README.md)
- Consolidate explorer functionality into main blockchain-explorer application

cli/genesis_multi_chain_dev.yaml

@@ -0,0 +1,22 @@
+description: Genesis template for multi-chain-dev
+genesis:
+  accounts: []
+  chain_type: topic
+  consensus:
+    algorithm: pos
+    authorities: []
+    block_time: 5
+    max_validators: 100
+  contracts: []
+  description: A multi-chain-dev chain for AITBC
+  name: Multi-Chain-Dev Chain
+  parameters:
+    block_reward: '2000000000000000000'
+    max_block_size: 1048576
+    max_gas_per_block: 10000000
+    min_gas_price: 1000000000
+  privacy:
+    access_control: open
+    require_invitation: false
+    visibility: public
+  purpose: multi-chain-dev