Start AI clip generation from a YouTube video. Returns a JSON object with project_id (string), status ('processing'), poll_url (string), and estimated_minutes (number). Processing is async -- use get_project_status to poll every 10-15 seconds, or provide a callback_url to receive a webhook POST when all clips are exported with download URLs.

Returns a JSON object with id, name, status (pending/processing/completed/completed_no_clips/failed), step, error, expected_clips, duration, created_at, and a clips array. Clips are sorted by score (highest first). Each clip has: id, title, duration, score, reason, clip_status (pending/exporting/completed/failed), download_url (string or null), quality, thumbnail_url, created_at, updated_at. The download_url is only available when clip_status is 'completed'. Poll every 10-15 seconds until project status is 'completed'.

Returns a JSON object with projects (array), total, limit, and offset. Each project has: id, name, status, step, expected_clips, clips_count, duration, created_at. Use the status filter to find only completed or failed projects.

Returns a JSON object with full clip details: id, project_id, title, duration, score, reason, export_status, export_quality (720p/1080p), is_exported, video_url, video_url_720p, video_url_1080p, thumbnail_url, created_at, updated_at.

Returns a JSON object with plan (string), credits_remaining (number), credits_total (number), period_start (ISO date), and period_end (ISO date). Call this before generate_clips to confirm the user has enough credits.