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/aitbc_cli/main.py

@@ -46,6 +46,7 @@ from .commands.node import node
 from .commands.analytics import analytics
 from .commands.agent_comm import agent_comm
 from .commands.deployment import deploy
+from .commands.cross_chain import cross_chain
 from .plugins import plugin, load_plugins
 
 
@@ -188,6 +189,7 @@ cli.add_command(node)
 cli.add_command(analytics)
 cli.add_command(agent_comm)
 cli.add_command(deploy)
+cli.add_command(cross_chain)
 cli.add_command(plugin)
 load_plugins(cli)