Update question generation skill with iterative agent pipeline

Rewrite skill to use 5-step agent architecture:
1. Generate question + correct answer (with fact verification)
2. Review/revise question quality
3. Generate 3 distractors by modifying correct answer
4. Review/revise distractor quality
5. Compile final JSON

Remove IDs and coordinates from skill output (added programmatically).
Tighten constraints: questions ≤50 words, answers ≤25 words,
distractors within 5 words of correct answer length.

Co-Authored-By: Claude (claude-opus-4-6) <noreply@anthropic.com>

Author: jeremymanning