feat: add Kiro CLI adapter

[mvanhorn]

Summary

Adds a Kiro CLI adapter to agent-manager so AI DevKit can detect, list, start, and route messages to Kiro CLI sessions, the same way it already does for Claude Code, Codex, Copilot, Gemini CLI, OpenCode, and Pi.

Why this matters

Closes the maintainer-declared work item in #109 ("Support Kiro CLI in agent-manager"). Kiro was the one requested coding agent not yet wired into the adapter layer, so agent list, agent start --type kiro, agent sessions --type kiro, and the channel bridge had no way to reach it.

Changes

• New KiroAdapter (packages/agent-manager/src/adapters/KiroAdapter.ts), mirroring the existing PiAdapter: process detection, PID-to-session tracker matching, defensive JSONL session parsing, conversation/listSessions support, and idle/waiting status. Reads sessions from ~/.kiro/cli/sessions and gracefully returns empty results when that directory is absent.
• Extended the AgentType union with 'kiro' and exported KiroAdapter from adapters/index.ts and agent-manager/src/index.ts.
• Registered kiro in the AGENTS registry (launch command kiro-cli; process matcher accepts the kiro-cli or kiro basename) and added it to StartableAgentType.
• Registered new KiroAdapter() in both AgentManager factories (cli/src/commands/agent.ts and cli/src/services/channel/channel-runner.ts), added the Kiro display label, extended the --type help text, and added 'kiro' to VALID_AGENT_TYPES.
• Updated the README agent-support table to list Kiro CLI.

Testing

• New KiroAdapter.test.ts (type identity, kiro-cli/kiro process matching with no false positives, session detection) — agent-manager suite: 435 passed.
• Updated sessions.test.ts, agent.test.ts, channel.test.ts, and StartAgentPane.test.ts for the new type/registration/cycle order — cli suite: 808 passed.
• nx run-many -t build -p agent-manager (swc + tsc typecheck) and nx run-many -t lint -p agent-manager cli both clean.

Fixes #109

AI was used for assistance.