v0.1.8

Pre-alpha. Platforms: Windows x86_64, Linux x86_64, macOS Apple Silicon (+ their meridian-connect tunnel binaries). macOS Intel dropped (dead macos-13 runner); Linux ARM64 pending pixi linux-aarch64 support. PyPI meridian-server 0.1.8 published. Includes this sprint's fixes (handoff truncation, fs-roots visibility, PWA, auth key rotate-and-dedup, responsive, doc upload, Connect download links).