[Question] SandboxTemplate.environment environment variables not applied to container #863

Problem Description

When passing custom environment variables via SandboxSpec.template.environment, these variables do not appear in the sandbox container's environment.

Reproduction Steps

1. Create a sandbox with environment variables using the Python SDK:

sandbox = client.create_sandbox(
    name="test-env",
    source="base",
    environment={
        "GATEWAY_URL": "http://10.156.113.180:8001",
        "GATEWAY_API_KEY": "test-key",
        "SANDBOX_ID": "test-env",
    },
)

2. Debug output confirms the environment variables are correctly serialized in the protobuf message (request.spec.template.environment contains these values)

3. After the sandbox is ready, run env inside the sandbox:

env | grep GATEWAY
# no output - environment variables are missing

Expected Behavior

Environment variables in template.environment should appear in the container's environment.

Actual Behavior

• Debug output confirms template.environment is correctly passed to the OpenShell server
• But running env shows no custom environment variables
• OpenShell default environment variables (like OPENSHELL_SANDBOX_ID, SSL_CERT_FILE, etc.) do appear

Verification Steps Taken

• prost protobuf serialization is correct: request.spec.template.environment contains all environment variables
• Rust build_env_list function should process template_environment: it calls apply_env_map(&mut env, template_environment)
• apply_env_map should upsert environment variables
• Tested with a simple MY_TEST_VAR=test_value - same result, environment variable not present

Environment

• OpenShell version: 0.0.29 (running k3s on OrbStack)
• Python SDK: locally built
• Similar issue was reported by feat: support custom sandbox entrypoint command #848's author - they tried passing OPENSHELL_SANDBOX_COMMAND via the environment map and it didn't work

Related Code

• crates/openshell-server/src/sandbox/mod.rs:
  • sandbox_template_to_k8s receives template_environment: &HashMap<String, String>
  • build_env_list calls apply_env_map(&mut env, template_environment)
  • apply_env_map should upsert environment variables

Possible Causes

1. prost deserialization issue with map<string, string> fields
2. Kubernetes-level environment variable injection issue
3. Or template.environment support was never fully implemented

Related issues: #848 (similar environment variable issue)