feat(config): enhance terminal environment variable management

- Updated .env.example to clarify terminal backend configuration and its relationship with config.yaml.
- Modified gateway/run.py to ensure terminal settings from config.yaml take precedence over .env, improving consistency in environment variable handling.
- Added mapping for terminal configuration options to corresponding environment variables for better integration.

.env.example

@@ -33,17 +33,16 @@ FAL_KEY=
 # TERMINAL TOOL CONFIGURATION (mini-swe-agent backend)
 # =============================================================================
 # Backend type: "local", "singularity", "docker", "modal", or "ssh"
-# - local: Runs directly on your machine (fastest, no isolation)
-# - ssh: Runs on remote server via SSH (great for sandboxing - agent can't touch its own code)
-# - singularity: Runs in Apptainer/Singularity containers (HPC clusters, no root needed)
-# - docker: Runs in Docker containers (isolated, requires Docker + docker group)
-# - modal: Runs in Modal cloud sandboxes (scalable, requires Modal account)
-TERMINAL_ENV=local
-
+# Terminal backend is configured in ~/.hermes/config.yaml (terminal.backend).
+# Use 'hermes setup' or 'hermes config set terminal.backend docker' to change.
+# Supported: local, docker, singularity, modal, ssh
+#
+# Only override here if you need to force a backend without touching config.yaml:
+# TERMINAL_ENV=local
 
 # Container images (for singularity/docker/modal backends)
-TERMINAL_DOCKER_IMAGE=nikolaik/python-nodejs:python3.11-nodejs20
-TERMINAL_SINGULARITY_IMAGE=docker://nikolaik/python-nodejs:python3.11-nodejs20
+# TERMINAL_DOCKER_IMAGE=nikolaik/python-nodejs:python3.11-nodejs20
+# TERMINAL_SINGULARITY_IMAGE=docker://nikolaik/python-nodejs:python3.11-nodejs20
 TERMINAL_MODAL_IMAGE=nikolaik/python-nodejs:python3.11-nodejs20