fix(scripts): resolve root env in worktrees

[emmepra]

Summary

• resolve .env from the shared repo root when scripts run inside git worktrees
• keep worktree-local runtime helpers able to inherit OpenRouter keys without duplicating .env files
• verified both public MASE and the private MIND worktree export the expected OpenRouter variables from repo-root .env

Verification

• bash scripts/runtime_env.sh <worktree-path> exports OPENROUTER_API_KEY, AGENT_LAUNCHER_OPENROUTER_API_KEY, and SIM_CTRL_OPENROUTER_API_KEY
• forced internal controller/launcher recreate picked up the resolved env values
• no-api_key MIND run launch succeeded after controller restart