File Viewer v2.1.2

File Viewer v2.1.2 improves archive-contained preview stability, mobile PDF layout, modular preset auto-discovery, installer guidance, and the documentation homepage experience.\n\nHighlights:\n- Fixed nested archive previews so PDFs and other documents are rendered from extracted entry streams instead of parent archive streams.\n- Improved compact/mobile PDF layout and navigation behavior.\n- Added automatic preset discovery through @file-viewer/vite-plugin and friendly install guidance for supported-but-not-loaded formats.\n- Refreshed README, ecosystem docs, demo artifacts, docs artifacts, and npm package tarballs.