v0.21.0

Summary

Enables consumers of @haklex/rich-agent-core and @haklex/rich-ext-ai-agent
to inject a custom LiteXML registry (with their own readers/writers) through
the AI agent stack — document serialization, tool XML parsing, and message
context all honour the provided registry. Internal callers without a registry
continue to use createDefaultRegistry() unchanged.

Breaking Changes

None — the new litexmlRegistry option is optional on every API it was added to.

Features

• @haklex/rich-agent-core: new LitexmlRegistryProvider / LitexmlRegistryOptions types and
  optional litexmlRegistry field on AgentExecutorConfig, DocumentContextOptions, and
  createDocumentTools. The registry is resolved via resolveLitexmlRegistry() and falls back
  to the default registry when absent.
• @haklex/rich-ext-ai-agent: AgentPanelPlugin, useAgentLoop, and AgentMessagesEngine
  accept an optional litexmlRegistry provider that is threaded through to the executor and
  text-selection context builders.

Bug Fixes

None this cycle.

Other

• chore(release-orchestrator): drop Shiro / rich-kit-shiro references from the release skill.

Bump rationale

Package	Signal	Bump
@haklex/rich-agent-core	New type exports (LitexmlRegistryOptions, LitexmlRegistryProvider) + new optional config fields	minor
@haklex/rich-ext-ai-agent	New optional litexmlRegistry prop/option on AgentPanelPlugin, useAgentLoop, AgentMessagesEngine	minor

max(bumps) = minor → shared version 0.20.0 → 0.21.0. Mode: incremental
(only rich-agent-core and rich-ext-ai-agent published).