feat(examples): demonstrate scale-set orchestration

[edersonbrilhante]

Description

Adds a multi-runner-scale-set example for the experimental multi-runner v2 interface. One deployment now demonstrates four lanes: Linux ARM64 webhook runners, ephemeral Linux x64 webhook runners with job retry, Linux x64 GitHub Actions scale-set runners, and Windows x64 webhook runners.

Shared V2 defaults place the VPC, subnets, Lambda architecture, and EC2 runner-binary settings in the global provider configuration. Each lane then supplies its own matcher, lifecycle, instance-type, and AMI overrides. The scale-set lane uses orchestration_provider.scale_set, reads its GitHub installation ID from the configured SSM parameter, and shares the global scale-set controller network. The example is also added to the Terraform verification matrix and documentation navigation.

Test Plan

• Ran terraform fmt -check -recursive.
• Ran terraform init -backend=false.
• Ran terraform validate.
• Repository pre-commit checks passed: Terraform format, validation with TFLint, and merge-conflict checks.

Related Issues

• Stacked on feat(scale-set): wire orchestration through runner config #5350.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None