Fixes: missing user_preferences column (use onboarding_dismissed column), PDF endpoint return type branching, WeasyPrint system deps, solo pro branding storage, screenshot size limit, supporting data PATCH endpoint, ExportPreviewModal download-only mode, guides as React components, illustration opacity and title size corrections, unknown guide slug handling. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>