Fix missing OpenCode engine case in aw_info model environment variable generation

[Copilot]

The compiler was generating invalid JavaScript syntax process.env. || "" for OpenCode engine workflows, causing SyntaxError: Unexpected token '||' in CI.

The switch statement in compiler_yaml.go that maps engine IDs to model environment variables was missing the opencode case, leaving modelEnvVar empty.

Changes:

• Added opencode case to switch statement, setting modelEnvVar = constants.EnvVarModelAgentOpenCode
• Recompiled affected workflows (dev.lock.yml, smoke-opencode.lock.yml)

Before:

switch engineID {
case "copilot":
    modelEnvVar = constants.EnvVarModelAgentCopilot
case "claude":
    modelEnvVar = constants.EnvVarModelAgentClaude
case "codex":
    modelEnvVar = constants.EnvVarModelAgentCodex
}
// modelEnvVar is empty for "opencode"

After:

switch engineID {
case "copilot":
    modelEnvVar = constants.EnvVarModelAgentCopilot
case "claude":
    modelEnvVar = constants.EnvVarModelAgentClaude
case "codex":
    modelEnvVar = constants.EnvVarModelAgentCodex
case "opencode":
    modelEnvVar = constants.EnvVarModelAgentOpenCode
}

Generated JavaScript:

// Before: process.env. || ""  ❌
// After:  process.env.GH_AW_MODEL_AGENT_OPENCODE || ""  ✅

Original prompt

Reference: https://github.com/githubnext/gh-aw/actions/runs/21036597930/job/60486139352#step:15:1

Lint js

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