Windows portable executable

[francomano]

Description

Build a standalone Windows .exe that works without requiring Go or any runtime dependencies.

Why it makes sense

Most Windows users don't have Go installed. A portable .exe (cross-compiled from Linux/macOS) would let anyone download and run ProxyDoctor directly.

Implementation

• Use in the build/release pipeline.
• Optionally use GoReleaser for cross-compilation and release automation.
• Ship as a single .exe with no external dependencies.

Acceptance Criteria

• with produces a working binary.
• The .exe runs on Windows 10+ without Go installed.
• README documents the download and usage.
• CI/build script includes the Windows build target.