feat: Add containerized execution with proxy for agent CLIs

[Mossaka]

• Introduced Dockerfile for agent base and proxy-init containers.
• Implemented proxy initialization script to set up iptables for transparent proxying.
• Enhanced Claude, Codex, and Copilot engines to support containerized execution with Docker Compose.
• Added Squid configuration for TPROXY-based proxying, allowing HTTP and HTTPS traffic.
• Updated workflow compiler to generate inline proxy configuration and Docker Compose files.
• Implemented logic to determine if engine execution requires proxy setup based on network permissions.
• Added support for copying logs and handling environment variables in containerized execution.

[Copilot]

Pull Request Overview

This pull request introduces containerized execution with proxy-based network traffic control for GitHub Agentic Workflows. The implementation adds transparent proxy support using Squid and iptables to enforce network restrictions at the container level, replacing the previous hook-based approach for network filtering.

Key changes include:

• Containerized agent execution using Docker Compose with three containers (agent, squid-proxy, proxy-init)
• TPROXY-based transparent proxying for both HTTP and HTTPS traffic
• Engine detection logic to automatically switch between direct and containerized execution

Reviewed Changes

Copilot reviewed 47 out of 48 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/workflow/engine_network_proxy.go	Core proxy configuration logic and Docker Compose generation
pkg/workflow/engine_docker_compose.go	Docker Compose template generation and command formatting
pkg/workflow/copilot_engine.go	Copilot engine containerized execution implementation
pkg/workflow/config/squid-tproxy.conf	Squid TPROXY proxy configuration template
pkg/workflow/compiler.go	Integration of proxy configuration generation into compilation
pkg/workflow/codex_engine.go	Codex engine containerized execution implementation
pkg/workflow/claude_engine.go	Claude engine containerized execution implementation with file close fix
containers/proxy-init/proxy-init.sh	Iptables and routing setup script for transparent proxy
containers/proxy-init/Dockerfile	Proxy initialization container definition
containers/agent-base/Dockerfile	Base agent container with Node.js and dependencies

Comments suppressed due to low confidence (3)

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