Load and merge skills from all configured sources.
Skills are loaded from multiple sources and merged with the following precedence (later overrides earlier for duplicate names):
Args: request: SkillsRequest containing configuration for which sources to load.
Returns: SkillsResponse containing merged skills and source counts.
Request body for loading skills.
Load public skills from OpenHands/skills repo
Load user skills from ~/.openhands/skills/
Load project skills from workspace
Load organization-level skills
Workspace directory path for project skills
Organization skills configuration
Sandbox skills configuration