feat: expose provider region lister

[intel352]

Refs GoCodeAlone/workflow#813.

Adds the optional IaCProviderRegionLister typed service so workflow admin surfaces can use provider-sourced AWS regions instead of the local fallback catalog.

Verification:

• GOWORK=off go test ./...

[Copilot]

Pull request overview

This PR adds support for the new optional typed IaC service IaCProviderRegionLister so Workflow admin surfaces can request an AWS region list from the plugin rather than relying on a host-side fallback catalog.

Changes:

• Advertises the IaCProviderRegionLister service in plugin.json.
• Implements ListRegions on the typed IaC server and adds tests verifying behavior + registration + manifest advertising.
• Bumps github.com/GoCodeAlone/workflow (and related indirect deps) to a version that includes the new typed service definitions.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
plugin.json	Adds the new typed service to the plugin’s advertised IaC services list.
internal/region_lister.go	Implements the IaCProviderRegionLister gRPC method (ListRegions).
internal/region_lister_test.go	Adds unit tests for region listing, service registration, and manifest parity.
internal/iacserver.go	Updates the server struct/interface assertions to include IaCProviderRegionLister.
go.mod	Bumps workflow dependency (and indirect deps) to a version containing the new service.
go.sum	Updates checksums corresponding to the dependency bumps.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 9 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

cmd/workflow-plugin-aws/plugin.json:13

• cmd/workflow-plugin-aws/plugin.json is the manifest embedded into the plugin binary (see cmd/workflow-plugin-aws/main.go). It currently does not list IaCProviderRegionLister under iacServices, so the host may not discover the new typed service even though it is implemented and advertised in the repo-root plugin.json.

  "minEngineVersion": "0.68.2",
  "iacServices": [
    "workflow.plugin.external.iac.IaCProviderRequired",
    "workflow.plugin.external.iac.IaCProviderEnumerator",
    "workflow.plugin.external.iac.IaCProviderDriftDetector",