[UPDATE] Add design-system-penpot skill

[egdev6]

Summary

Create a reusable design-system-penpot skill that codifies naming, page organization, coverage heuristics, and screenshot rules for Penpot-based design-system workflows.

Scope

• define naming conventions
• define per-page structure
• define screenshot criteria for GitHub Projects
• define component-specific heuristics for Button, Input, and Card
• define rules for reporting gaps and coverage

Acceptance Criteria

• the skill is usable by a Penpot executor agent
• the rules are explicit and unambiguous
• the skill is compatible with the new MCP tools

Tasks

• create the skill file
• define activation triggers
• define canonical page structure
• define naming rules
• define heuristics for Button, Input, and Card
• define output rules for GitHub Projects
• add explicit limits (do not invent missing states, do not perform destructive edits)
• validate compatibility with penpot-design-executor

Additional notes

The skill provides reusable design-system judgment; it does not replace the runtime bridge or the executor.