Debug launches only copied the explicit env map into the DAP launch
arguments and dropped the configuration's .env files, which Run loads
via ide_run::envfile. Add a run_env_files command that loads the files
with the same loader over the system environment, and merge the result
under the explicit variables when building debug launches (generic,
plugin-hosted and java-debug paths); explicit variables still win and a
missing file fails the launch with the same error Run reports.
Fixes#753 (comment): .env applied in Run but ignored in Debug.
arookieofc
14e4881418