Separate cmompiler name from version in json schema of buildevents

json payload returned from build events API presents compiler and version in a single string. Suggestion to split this into separate fields -- one for compiler name ('gcc') and another for compiler version ('14'). This would make it easier to configure clinets to pick up builds by a given compiler independent of the version. We can keep the existing "compiler" key for backward compatibility.

For example, Here is a URL for getting a single build event:
https://kernelci-api.westus3.cloudapp.azure.com/latest/events?state=available&kind=kbuild&limit=1&recursive=true&from=2026-07-16T18:18:03.801000

json payload retuned from it contains a 'data' section with the compiler documented like this:

"compiler": "gcc-14",

Start with the single-build-events URL in the issue and inspect the JSON schema and response data section for the existing compiler field. Define separate compiler name and version fields while preserving the existing compiler key, then verify the response remains backward compatible.

Written by the indexing model from the issue text.