chore: migrate agent base image from Alpine to Debian

[ereslibre]

Migrate the agent container base image from node:24-alpine (Alpine Linux) to node:lts (Debian). This switch to a glibc-based distribution reduces compatibility issues with prebuilt binaries and tools (e.g., Cursor Agent), minimizing the need for the nix-based glibc workaround (as glibc incompatibilities might still arise).

Closes: #493

Changes

Container image (Alpine → Debian)

• Switched Dockerfile base image from node:24-alpine to node:lts
• Replaced apk package commands with apt-get equivalents across all sandbox language, package manager, and task manager install scripts
• Replaced corepack enable pnpm with npm install -g pnpm in the builder stage
• Replaced wget with curl for downloading the package-manager-mcp binary
• Replaced Alpine's uv package with the official uv install script
• Updated sudoers files (1-sudoers-setup, 2-sudoers-cleanup) to reflect Debian's default group set
• Changed the default shell from /bin/sh to /bin/bash in Docker and Podman sandbox shells
• Replaced Alpine-specific Rust install (apk add rustup) with rustup.rs installer
• Replaced Alpine-specific Just install with the official just install script
• Updated network filtering script to use apt-get for iptables installation instead of apk

Other changes

• Bumped package-manager-mcp-server version from v0.2.0 to v0.3.0
• Agent process now explicitly exits with a proper exit code (0 on success, 1 on failure) after finishing the workflow
• Updated documentation (agent-images.md, faq.md) to reflect the Debian base image

Notes

The nix-based glibc workaround previously needed for tools like the Cursor Agent is no longer required and has been removed from the documentation. The nix package itself is retained in the image for other purposes.

[Angelmmiguel]

Added a few comments! Great job 😄

[ereslibre]

Okay, I have just run a sanity check with all supported agents, and it's looking good!

[Angelmmiguel]

LGTM!