Fix struct duplication between internal/model and tools/publisher

[domdomegg]

I sincerely apologize for the disruption. This PR was accidentally closed due to an unintended git history rewrite operation that broke the connection between branches. The operation has been reverted and I'm now recreating the affected PRs.\n\nOriginal PR: #217

[rdimitrov]

@domdomegg - It's alright, no worries 🍻 I'll make sure to address your feedback and rebase it 👍

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[rdimitrov]

@domdomegg - hey, I don't have the rights to mark the PR out of draft and edit the PR description so I'll place it as a comment here -

Motivation and Context

• Remove duplicated structs in tools/publisher and ensure the CLI uses the same schema as the registry.
• Reduce maintenance burden and keep publisher output aligned with the public API.

What’s changed

• Switched publisher to import github.com/modelcontextprotocol/registry/pkg/model (no internal/... dependency).
• Removed local struct definitions in tools/publisher/main.go.
• createServerStructure(...) now returns model.ServerDetail; only necessary fields are populated.
• Output is minimal due to omitempty tags in pkg/model. Note: repository.id currently lacks omitempty, so it appears as an empty string.

Example output

{
  "name": "io.github.example/simple-server",
  "description": "A simple MCP server",
  "status": "active",
  "repository": {
    "url": "https://github.com/example/simple-server",
    "source": "github",
    "id": ""
  },
  "version_detail": {
    "version": "1.0.0"
  },
  "packages": [
    {
      "registry_name": "npm",
      "name": "io.github.example/simple-server",
      "version": "1.0.0",
      "runtime_hint": "npx"
    }
  ]
}

How Has This Been Tested?

• Built the publisher and generated a sample server.json; verified unset fields are omitted where omitempty is present.

Breaking Changes

• None.

Types of changes

• Refactor / code hygiene.

Related

• Add omitempty to repository.id or introduce a minimal DTO for publisher output to prevent accidental inclusion of registry-managed fields (already addressed via #285)
• Continues the work from the closed PR #217

[rdimitrov]

Regarding this #217 (review) comment - I assume now that we have the omitempty tags set and they work as intended it shouldn't be needed to do the split you suggested, right?

[domdomegg]

Yep I think this is correct! I think also because of the extensions spec that we've agreed on the model can be exactly the same between publisher and registry :)