Allow CD Version name to be free-form

What does this MR do and why?

This MR lets a CD Version be created with a free-form name, instead of only ever being auto-created from a container registry push.

A Cd::Version records one version of an artifact tied to a Cd::ArtifactSource. Until now, GitLab could only create a version automatically, when it saw a container image get pushed to a registry it watches, and the version name had to match strict registry-tag naming rules. That meant there was no way to record a version for an artifact hosted somewhere GitLab never receives a push event from, and no way to give a version a name that doesn't look like a registry tag. This MR adds a verified flag on Cd::Version: versions created the old way (from a real push event) stay verified: true and still have their name format checked, but a version can now also be created with verified: false, which skips the name format check and accepts any free text. A new service and GraphQL mutation, cdVersionCreate, let a caller record a version this way, and every version created through this mutation comes out verified: false, since it's telling GitLab about something it didn't observe itself.

The cdVersionCreate mutation is gated behind the ai_native_deploy feature flag, like the rest of CD, and is marked GraphQL Experiment.

How to test

1. Seed data (Rails console)

organization = Organizations::Organization.first
application = Cd::Application.find_or_create_by!(organization: organization, name: 'test-app')
service = Cd::Service.find_or_create_by!(application: application, name: 'test-service')
artifact_source = Cd::ArtifactSource.find_or_create_by!(service: service, name: 'test-artifact-source') do |as|
  as.source_ref = 'external/registry/test'
end

Feature.enable(:ai_native_deploy)

puts artifact_source.to_global_id

2. Call the mutation (GraphQL Explorer at /-/graphql-explorer)

mutation($artifactSourceId: CdArtifactSourceID!, $name: String!) {
  cdVersionCreate(input: { artifactSourceId: $artifactSourceId, name: $name }) {
    version {
      id
      name
      verified
    }
    errors
  }
}

Variables (use the ID printed in step 1):

{
  "artifactSourceId": "gid://gitlab/Cd::ArtifactSource/1",
  "name": "my release / build 1+rc"
}

Expected: the mutation succeeds, returns the new version with verified: false and the free-text name unchanged, and errors is empty.

References

https://gitlab.com/gitlab-org/gitlab/-/work_items/616346

https://gitlab.com/gitlab-org/gitlab/-/work_items/617187

Screenshots or screen recordings

No UI change — backend and GraphQL only.

How to set up and validate locally

1. Seed an organization, application, service, and artifact source, and enable the ai_native_deploy feature flag.
2. Call the cdVersionCreate mutation with a free-text name (spaces, slashes, or other characters not allowed by the old registry-tag format check).
3. Confirm in the response, or in the database, that the version was created with verified: false and no validation errors.

MR acceptance checklist

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