[feature] AI Copilot for Skills

[ivicac]

Summary

Add AI Copilot integration for Agent Skills — enabling AI-assisted skill creation, editing, and SKILL.md content generation through the CopilotPanel.

Features

1. Create from AI (CopilotPanel-powered)

The existing "Create with AI" option in the skills panel should use the CopilotPanel to interactively guide the user through skill creation:

• User describes the desired skill behavior in natural language
• Copilot asks clarifying questions (scope, triggers, edge cases)
• Copilot generates well-structured SKILL.md content following the Agent Skills specification — proper YAML frontmatter (name, description), clear step-by-step instructions, decision logic, examples, and reference sections or script stubs when appropriate
• User can iterate on the generated content before saving
• Copilot packages the result as a .skill archive and creates it via the existing createAgentSkillFromInstructions API

2. AI-Assisted Skill Editing

When viewing an existing skill in the detail view:

• Copilot can suggest improvements to SKILL.md instructions
• User can ask Copilot to refine, expand, or restructure skill content
• Copilot understands the skill's current content and can make targeted edits

Context

This builds on the Agent Skills feature (#4545) which provides CRUD operations for skills. The Copilot integration uses the existing CopilotPanel infrastructure and useCopilotStore.

Acceptance Criteria

• "Create with AI" option opens CopilotPanel with skill creation context
• Copilot can generate complete SKILL.md from natural language description following the Agent Skills specification
• Generated skills include proper YAML frontmatter, structured instructions, and optional reference/script sections
• Users can iterate on generated content before saving
• Copilot context includes current skill content when editing existing skills