Problem

Sensei v1.3.0 has advisory check 18 — progressive disclosure — that flags SKILL.md bodies that should move detailed content to references/:

1. SKILL.md body exceeds 500 lines
2. Large code blocks (>50 lines) inline that could be in references
3. Detailed API reference or config docs inline

Waza has no progressive disclosure check.

Expected Behavior

Add a ProgressiveDisclosureChecker to internal/checks/ that:

• Counts lines in SKILL.md body
• Detects large inline code blocks (>50 lines)
• Suggests moving detailed content to references/ directory
• Advisory only

References

• spboyer/sensei references/scoring.md — advisory check 18
• agentskills.io spec — recommends under 500 lines

Acceptance Criteria

• New checker in internal/checks/
• Line count check (>500 = warning)
• Large code block detection
• Advisory status
• Tests