Feature: Native DevContainers Backend via Porthole/wslc

[celloza]

Summary

Add native VS Code DevContainers backend support so Porthole (wslc) can act as a Docker Desktop alternative for local containerized development workflows.

Problem

DevContainers are now a default development workflow in VS Code, but most setups implicitly depend on Docker Desktop as the runtime backend. This blocks developers who want a Windows-native wslc/Porthole-first workflow.

Proposal

• Register Porthole as a valid DevContainers backend integration target.
• Intercept or adapt DevContainer lifecycle operations to wslc session operations:
  • build/rebuild
  • create/start/stop
  • exec/attach
• For workspace-open flow:
  • clone/open repo in VS Code
  • Porthole creates isolated wslc Session
  • workspace is mounted via virtiofs
  • IDE attaches into container seamlessly
• Provide compatibility layer for common .devcontainer/devcontainer.json features:
  • image/Dockerfile builds
  • environment variables
  • forwarded ports
  • postCreate/postStart hooks

Sexy Factor

Porthole becomes a true daily-driver, drop-in backend replacement for .NET and web developers using DevContainers, without requiring Docker Desktop.

Integration Notes

• Preserve Porthole App/Core/Tray boundaries and typed IPC contracts.
• Keep Microsoft.WSL.Containers usage in tray/backend layers.
• Minimize user-facing setup friction (ideally one-time backend registration).

Acceptance Criteria

• User can open a repo with a valid .devcontainer config and choose Porthole backend.
• DevContainer build + up completes using wslc session primitives.
• Workspace mount via virtiofs works for file edits, watch tasks, and toolchains.
• VS Code attach experience behaves equivalent to standard DevContainers flow.
• Port forwarding and lifecycle hooks function for common scenarios.
• Clear diagnostics shown for unsupported devcontainer.json features.

Out of Scope (initial cut)

• 100% parity with every Docker-specific DevContainers edge case.
• Non-VS Code IDE integrations.

Suggested Labels

enhancement, devcontainers, vscode, backend