fix: don't create files for resources/datasources that don't expose qualifying create/read endpoints

[jasondamour]

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Summary by cubic

Skip generating Terraform resource and data source files when a tag lacks a create or read endpoint. This avoids broken builds and removes unused model files.

• Bug Fixes

  • Track qualifying tags and delete non-resource/data-source files in postProcessFile (_resource.go, _data_source.go, _model.go).
  • Only register resources with create and data sources with read via isResource/isDataSource in provider.mustache.
  • Treat read-only fields as computed, not required.
  • Log a warning when the ID field can’t be resolved from the read response.

• Dependencies

  • Update go.mod template: set module path to github.com/teamlumos/knowledge-server and add indirect deps needed by the framework.

^{Written for commit 5f87a14. Summary will update on new commits.}