#593 Official extension for GitHub repository configuration (environments, variables, secrets)

Problem

Managing GitHub Environment variables and secrets as infrastructure-as-code requires a custom extension today. Users building CI/CD pipelines need to:

• Declare all environment variables and secrets for a GitHub Environment in a model definition YAML
• Batch-provision them in one method call (not N separate calls)
• Source secret values from swamp vault expressions
• Track what was set via data artifacts

There is no official @swamp/github extension covering this.

Proposed solution

An official @swamp/github/environments extension type with:

• provision method — batch-set variables and secrets for a GitHub Environment in one call

  methods:
    provision:
      arguments:
        environment: ${{ inputs.environment }}
        variables:
          AWS_ROLE_ARN: arn:aws:iam::123456789:role/my-role-${{ inputs.environment }}
          DEPLOY_REGION: us-east-1
        secrets:
          API_TOKEN: ${{ vault.get("my-vault", "api-token") }}
          DB_PASSWORD: ${{ vault.get("my-vault", "db-password") }}

• setVariable / set methods — single-item operations for ad-hoc use
• Secret encryption via GitHub's environment public key (libsodium sealed box)
• Data artifacts confirming what was set (variable names, secret names, timestamps — never values)

A companion @swamp/github/repository type would cover repo-level variables and secrets with the same pattern.

Alternatives

Users currently build custom extensions using @octokit/rest and libsodium-wrappers. This works but duplicates effort across projects and lacks the discoverability of an official extension.