- Add kiro_discovery.rs: binary detection (PATH, login shell, known paths)
- Add kiro_cli.rs: streaming via stdin, ANSI stripping, MCP config merge
- Register Kiro in ai_agents.rs enum, status, and dispatcher
- Add 'kiro' to settings normalization
- Add Kiro to frontend agent definitions and helpers
- Update test for agent cycling
Kiro uses plain text streaming (not JSON) so it has its own stream
handler rather than using cli_agent_runtime::run_ai_agent_json_stream.
MCP config merges into existing .kiro/settings/mcp.json to preserve
user-configured servers. Prompt is passed via stdin to avoid E2BIG.