fix: support repository rename in github_actions_repository_oidc_subject_claim_customization_template

[acouvreur]

Related to #3180

Also note: #3582 changes the same resource file to add use_immutable_subject and sub_claim_prefix. The second PR to merge will need a rebase.

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Before the change?

• When you rename the repository, the plan changes the template in place on the new name, but the resource cannot tell a rename from a different repository.
• When you change repository to a different repository, the old repository keeps its custom template.
• The resource uses the deprecated non-context CRUD functions and calls Read at the end of Create and Update.

After the change?

• New computed repository_id attribute and diffRepository in CustomizeDiff. A rename is an in-place update. A change to a different repository forces a new resource.
• State upgrader (v0 to v1) adds repository_id with the shared migrateRepositoryWithID helper.
• The resource ID stays the repository name, so existing state and import IDs do not change.
• Context-aware CRUD, tflog, and no read-after-write ([MAINT]: Remove read call from create/update #2892).
• Delete treats a 404 as success.
• The docs now list repository and repository_id.

Pull request checklist

• Schema migrations have been created if needed (example)
• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes
• No

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🤖 Generated with Claude Code

[github-actions]

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[acouvreur]

@deiga @stevehipwell let me know if I can do anything to facilitate the review of this change

[stevehipwell]

Thanks for the PR @acouvreur. Could you add an empty test for the migration so we know what we need to enables when we have a pattern. Also you may want to take a look at #3476 which is the latest migration work I've done and should be the best pattern to follow.

[acouvreur]

@stevehipwell I've updated the PR to the latest recommendations and architecture guidelines, can you take a look?