Add crypto provider catalog

[intel352]

Summary

• instantiate the public workflow-plugin-crypto repo from the plugin scaffold
• add a public crypto provider catalog package for workflow-compute full-node profiles
• strip scaffold/runtime capability placeholders and validate the plugin manifest

Verification

• GOWORK=off go build ./...
• GOWORK=off go test ./... -v -race -count=1
• GOWORK=off go vet ./...
• GOWORK=off go run ./cmd/wfctl plugin validate-contract /Users/jon/workspace/workflow-plugin-crypto (from /Users/jon/workspace/workflow)
• git diff --check