Margins v0.3.1

Official Margins binaries are built from the private source-of-truth and include
non-public platform capture adapters composed with the public open-core CLI.
The open-source crates and export remain available in this repository for audit,
extension, and source builds; building that export alone does not reproduce the
official recording binary.

No recording data or hosted capture service is added by this packaging model.
Capture remains local to the installed application.