Replace generateChittyID with @chittyos/chittyid-client across codebase

- Update chittyrouter-gateway.js to use ChittyIDClient.mint()
- Update cross-session-sync index.ts with official client
- Update client-integration.js for sync sessions
- Update ai-github-bridge.ts for AI session IDs
- Remove .bak backup files
- All IDs now use SERVICE OR FAIL principle

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: chitcommit