Expand built-in skill ecosystem

[Xunzhuo]

Goal

Expand the built-in skill ecosystem so Elephant Agent ships more useful native capabilities with consistent governance and testing.

Scope

• Built-in skill discovery and registration conventions
• Skill packaging, metadata, and capability descriptions
• Safety and permission boundaries for built-in skills
• Test strategy for skill behavior and regressions
• Documentation for adding and maintaining built-in skills

Acceptance Criteria

• A built-in skill expansion plan defines target categories and acceptance standards.
• Skill metadata is sufficient for routing, display, and safety decisions.
• At least one new built-in skill follows the standard path end to end.
• Tests cover registration and representative execution behavior.
• Documentation explains how future skills should be added.