Add multi-platform release builds for 0.9.0 (closes #138).

BUILD.md

@@ -20,9 +20,15 @@ Packages are written below `target/release`. The macOS bundle uses the ICNS icon
 
 Windows packaging requires the MSVC Rust toolchain, Visual Studio Build Tools with C++ support, and the Windows SDK. Build each package on its target operating system; these commands do not cross-package installers.
 
+## Automated tagged releases
+
+Pushing a tag runs `.gitea/workflows/release.yml` on Linux arm64. The workflow builds Linux arm64 natively, cross-links Linux x64 with Ubuntu's amd64 development libraries and GNU cross-toolchain, uses Cargo Zigbuild for macOS, Cargo Xwin for Windows x64, and `bds-release` for every packaging and Gitea API operation. It does not require host installations of Python, `curl`, `tar`, `hdiutil`, or NSIS.
+
+The workflow publishes CLI/MCP and desktop artifacts for Linux and macOS on arm64 and x64, plus Windows x64. Linux desktop binaries dynamically use the target system's GTK 3, WebKitGTK 4.1, and libxdo runtime packages. macOS desktop artifacts are ad-hoc-signed `.dmg` files, Unix artifacts are `.tar.gz`, and Windows artifacts are `.zip` files containing the native `.exe` application and its runtime DLLs. The Gitea release remains a draft unless every build and upload succeeds.
+
 ## macOS system requirements
 
-- macOS 13 (Ventura) or later
+- macOS 26 or later
 - Apple Silicon or Intel Mac with Metal or Vulkan support (required by Iced's wgpu backend)
 
 ## Linux system requirements (optional, for CI or cross-platform development)