feat(openapi3): import readOnly/writeOnly as visibility decorators

[Copilot]

The import tool ignored readOnly and writeOnly properties, breaking import/emit symmetry since the emitter already generates these from @visibility decorators.

Changes

• Type definitions: Added missing writeOnly property to OpenAPI3Schema and OpenAPISchema3_2
• Import conversion:
  • readOnly: true → @visibility(Lifecycle.Read)
  • writeOnly: true → @visibility(Lifecycle.Create)
  • Mutual exclusivity validation (warns and ignores both if both present)
• Tests: Coverage for all scenarios including nested properties and arrays

Example

Before:

properties:
  id:
    type: string
    readOnly: true

model Widget {
  id: string;  // readOnly lost
}

After:

model Widget {
  @visibility(Lifecycle.Read) id: string;
}

Original prompt

---

This section details on the original issue you should resolve

<issue_title>import tool - support importing readonly and writeonly</issue_title>
<issue_description>### Clear and concise description of the problem

The import tool currently does not support importing readOnly: true or writeOnly: true as a visibility decorator. We should add support for that because the emitters support the decorator, so the import/emit process is not symmetrical today.

Today the following OpenAPI descriptions

components:
  schemas:
    Widget:
      type: object
      required:
        - id
        - weight
        - color
      properties:
        id:
          type: string
          readOnly: true
        weight:
          type: integer
          format: int32
        color:
          type: string
          enum:
            - red
            - blue

or

components:
  schemas:
    Widget:
      type: object
      required:
        - id
        - weight
        - color
      properties:
        id:
          type: string
          writeOnly: true
        weight:
          type: integer
          format: int32
        color:
          type: string
          enum:
            - red
            - blue

both result to

model Widget {
  id: string;

  weight: int32;
  color: "red" | "blue";
}

As if the read/write only properties are absent.

It should instead result in

model Widget {
+  @visibility(Lifecycle.Read)
  id: string;

  weight: int32;
  color: "red" | "blue";
}

In the case readOnly is present

model Widget {
+  @visibility(Lifecycle.Create)
  id: string;

  weight: int32;
  color: "red" | "blue";
}

In the case writeOnly is present.

Also those properties should be treated as mutually exclusive and an error should be reported + both ignored in case they are both present.

Checklist

• Follow our Code of Conduct
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.</issue_description>

<agent_instructions>use conventional commits.
run the formatting commands.
run the changelog command.
start by defining the unit tests first.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes import tool - support importing readonly and writeonly #9741

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