Flyfish Viewer 2.1.1

Flyfish Viewer 2.1.1 publishes the full 2.x ecosystem, including core, presets, renderers, framework components, demo, docs, and offline distribution artifacts.\n\nHighlights:\n- Markdown frontmatter cleanup for cleaner preview output.\n- Safer PDF asset defaults for root deployments.\n- XLS/XLSX drawing preview sizing fixes.\n- Toolbar item and permission metadata synchronized across packages.\n- Demo, documentation, official site, npm packages, and release artifacts are aligned to 2.1.1.