Implement runtime support for issue remediation

[codejasleen]

Summary

This PR completes the runtime implementation for Issue Remediation, building on the previously introduced provider interface and remediation configuration.

Changes

• Add the Issue remediation engine.

• Implement runtime support for:

  • creating GitHub issues when remediation is enabled
  • closing previously created issues when remediation is disabled

• Persist issue metadata to avoid creating duplicate issues while a remediation remains active.

• Wire the issue remediation type into the remediation engine.

• Enable type: issue in remediation validation.

• Add validation for IssueRemediation configuration.

• Add unit tests covering:

  • issue creation
  • issue creation failures
  • existing issue reuse
  • issue closure
  • issue closure without stored metadata

• Regenerate protobuf, OpenAPI, and documentation after enabling the new remediation type.

This makes issue a functional remediation type end-to-end.

Fixes #(related issue)

Testing

Verified with:

go test ./internal/engine/actions/remediate/issue
go test ./internal/engine/actions/remediate/...
go build ./...

Future work

Potential follow-up improvements include:

• configurable issue labels

• configurable issue assignees

• optional comment when automatically closing an issue

• support for reopening previously closed remediation issues

[coveralls]

coverage: 60.844% (-0.03%) from 60.872% — codejasleen:issue-remediation-runtime into mindersec:main