refactor(indentation): Apply codebase-wide 1-space ultra-compact refactor. Formatted 21 core modules and tests.

shell_runner.py

@@ -33,7 +33,7 @@ def _build_subprocess_env() -> dict[str, str]:
  prepend_dirs = _ENV_CONFIG.get("path", {}).get("prepend", [])
  if prepend_dirs:
   env["PATH"] = os.pathsep.join(prepend_dirs) + os.pathsep + env.get("PATH", "")
- # Apply [env] key-value pairs, expanding ${VAR} references
+  # Apply [env] key-value pairs, expanding ${VAR} references
  for key, val in _ENV_CONFIG.get("env", {}).items():
   env[key] = os.path.expandvars(str(val))
  return env