* Add agent-customization skill with primitives documentation * Update assets/prompts/skills/agent-customization/primitives/workspace-instructions.md Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * fix: rename agentCustomizationSkill setting to follow Advanced naming convention * Updated skills.md based on spec --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>