What does this PR do?

Passes active skill/config passthrough environment variables into remote terminal backends.

This is the follow-up to the skill readiness fix. The first PR makes skill env var readiness env-driven and restores passthrough registration. This follow-up ensures those active passthrough vars are actually delivered to remote terminal execution paths.

This branch is intentionally stacked on top of:

• fix/skill-env-remote-readiness

Relationship to the first PR

This PR depends on the readiness fix branch and is intended for review as a stacked follow-up.

The new work here is:

• shared passthrough env resolution in the environment base layer
• remote backend injection for Docker, Daytona, Modal, Singularity, and SSH
• regression tests for helper resolution and representative remote backends

Changes Made

• added a shared helper in tools/environments/base.py to resolve active passthrough env vars from:
  • tools.env_passthrough.get_all_passthrough()
  • os.environ
  • load_env() as fallback
• updated Docker execution to pass resolved vars via docker exec -e
• updated Daytona, Modal, Singularity, and SSH execution to prepend shell-quoted export KEY=...; statements before the command
• added regression coverage for:
  • passthrough env resolution helper behavior
  • Docker env injection
  • Daytona env export injection
  • SSH env export injection

How to Test

1. Run:
   uv run --extra dev python -m pytest tests/tools/test_skills_tool.py tests/tools/test_skill_env_passthrough.py tests/tools/ test_env_passthrough.py tests/tools/test_docker_environment.py tests/tools/test_daytona_environment.py tests/tools/test_ssh_environment.py -q
2. Load a skill that registers a required env var into passthrough
3. Run a remote terminal backend such as Docker, Daytona, or SSH
4. Confirm the remote command can read the passthrough env var

Test Results

• 152 passed, 11 skipped

Platform Tested

• macOS

Notes

This PR is stacked on top of the readiness-fix branch. After the first PR merges, I will rebase this branch onto upstream/main so the
final upstream PR contains only the remote backend passthrough changes.