Claude Skills: effort field support (Opus 4.6)

[claude-yolo]

Skills Now Support Effort Override

WHY this matters: Per-skill performance control without session changes.

What's New

• Skills can set effort field to override session effort levels
• Options: low, medium, high, max (Opus 4.6 only)
• Default: inherits from session

Use Cases

• Heavy analysis skills → effort: max
• Quick lookup skills → effort: low
• Mixed workflows with different performance needs

Related: PR #777