Port complete boundary implementation

[f0ssel]

This PR ports the complete boundary network isolation tool implementation.

Features

• Process-level network isolation using Linux namespaces and macOS process groups
• HTTP/HTTPS interception with transparent proxy and TLS certificate injection
• Rule-based access control with wildcard pattern matching for URLs
• Cross-platform support for Linux and macOS
• Unprivileged mode for restricted environments using proxy environment variables
• Comprehensive logging and request auditing

Implementation

• CLI interface with serpent-based command structure
• Modular architecture: audit, jail, proxy, rules, TLS packages
• Production-ready CI/CD with automated building, testing, and releases
• Cross-platform builds for Linux (x64/ARM64) and macOS (Intel/Apple Silicon)

Usage

# Allow only requests to github.com
boundary --allow "github.com" -- curl https://github.com

# Allow specific methods
boundary --allow "GET,HEAD github.com" -- npm install

# Unprivileged mode (no sudo required)
boundary --unprivileged --allow "*.npmjs.org" -- npm install

[bcpeinhardt]

The "allow" bit should be removed