Skill system with WASM-sandboxed runtime, plugin loading, and registry.

This crate defines the skill abstraction used by Argentor agents, including dynamic loading of WASM plugins, a central registry, and markdown-based prompt skills.

Main types

• [Skill] — Trait that every executable skill implements.
• [SkillDescriptor] — Metadata describing a skill's name, parameters, and capabilities.
• [SkillRegistry] — Central registry for discovering and invoking skills.
• [WasmSkillRuntime] — Wasmtime-based sandbox for running untrusted skill plugins.
• [SkillLoader] — Loads WASM skill plugins from configuration.
• [MarkdownSkill] — A skill defined via a Markdown file with YAML frontmatter.