[FEATURE]: Refactor models.go, apply Effective Go, and add Playwright tests

[manthysbr]

Issue Type:

• 🐞 Bug Report
• ✨ Feature Request

Relevant Domain (if applicable):

• Go, API Models, Testing

Detailed Description:

The models.go file needs to be refactored to align with best practices outlined in "Effective Go". This refactoring should improve code readability, maintainability, and efficiency.

As part of this task, comprehensive tests need to be written for the updated models.go. These tests should include:

1. Unit tests for the data structures and any associated logic within models.go.
2. Integration/E2E tests using Playwright to interact with the application's Swagger UI (or a relevant API endpoint that reflects the model structures). These Playwright tests should verify that the API, as exposed through Swagger, correctly handles and represents the data defined in models.go after refactoring.

The Copilot agent should:

• Analyze the current models.go.
• Identify areas for improvement based on "Effective Go" principles.
• Implement the refactoring changes.
• Write unit tests for the refactored code.
• Write Playwright tests that:
  • Navigate to the Swagger UI page (please determine the correct URL, likely /swagger/index.html or similar for this application).
  • Interact with relevant API endpoints on the Swagger page that utilize the structures defined in models.go.
  • Validate request/response schemas and example data against the refactored models.
• Ensure all new and existing tests pass.

The agent should leverage its Playwright MCP capabilities to perform the browser interactions required for the E2E tests. It should also be able to access and understand the "Effective Go" documentation (e.g., from https://go.dev/doc/effective_go) to inform the refactoring.

Steps to Reproduce (for bugs):

...

Expected Behavior:

• models.go is refactored according to "Effective Go" principles.
• New unit tests are added for models.go with good coverage.
• New Playwright E2E tests are added that validate the models via the Swagger UI.
• All code compiles and all tests pass.
• A pull request is opened with the changes.

Current Behavior (for bugs):

N/A

Context/Environment:

• Hefestus API Version (if known): latest from main branch
• Ollama Model Used (if relevant): N/A
• Operating System: N/A (agent will use its own environment)
• Go Version (if developing/compiling): As per repository's go.mod or latest stable Go.
• domains.json Configuration (if relevant and not sensitive): N/A
• Example Request (if applicable and not sensitive):

  {
    "error_details": "...",
    "context": "..."
  }

• Example Response (if applicable and not sensitive):

  {
    "error": {
      "cause": "...",
      "solution": "..."
    },
    "message": "..."
  }

Possible Solution (optional):

The agent should review "Effective Go" (https://go.dev/doc/effective_go) and apply relevant idioms and practices to models.go. For Playwright tests, it should identify key API endpoints in the Swagger UI that exercise the data models and write tests to cover their request/response structures.

Additional Information:

The primary goal is to improve the quality and test coverage of models.go. Ensure that Playwright is correctly utilized for testing the API's interaction with these models through its Swagger interface.