Fix webhook docs: remove xetEnabled, add move action, document env vars (#2320)
- webhooks.md: Remove xetEnabled from updatedConfig (only private is supported); add note about hidden comment content being undefined
- webhooks-guide-auto-retrain.md: Add missing "move" webhook event action
- jobs-webhooks.md: Document all webhook environment variables (WEBHOOK_PAYLOAD, WEBHOOK_REPO_ID, WEBHOOK_REPO_TYPE, WEBHOOK_SECRET)
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>