Honor pre-set slugs and refine slug generation

[gregupton]

Summary

• add string type hint to findBySlug
• skip slug regeneration when a model already has a slug
• remove default fallback when resolving slug source
• document manual slug usage and update changelog
• fix changelog order so version 1.1.5 precedes 1.1.4

Testing

• php composer.phar install (fails: curl error 56 while downloading https://repo.packagist.org/packages.json: CONNECT tunnel failed, response 403)
• ./vendor/bin/phpunit (fails: No such file or directory)

---

https://chatgpt.com/codex/tasks/task_e_68bc5b28e8b4832cbc3e8489d05a7878

[chatgpt-codex-connector]

Codex Review: Here are some suggestions.

Reply with @codex fix comments to fix any unresolved comments.

About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you open a pull request for review, mark a draft as ready, or comment "@codex review". If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex fix this CI failure" or "@codex address that feedback".

[chatgpt-codex-connector]

[P1] Early return prevents configured slug updates

generateSlug now returns whenever the slug column already has any value (if (! empty($this->{$slugColumn})) { return; }). After the first save every model has a non-empty slug, so this branch executes on every update and the method never reaches the logic that regenerates the slug when slugUpdatable is enabled and the source field is dirty. This regresses existing behaviour and causes tests like it('updates the slug on update') to fail because slugs no longer update when titles change unless the slug attribute is manually cleared.

Useful? React with 👍 / 👎.