Convert the procedural hooks to OOP hook classes in the Varbase SEO module

Problem/Motivation

Drupal 11 introduced object-oriented hook implementations via the #[Hook] attribute (change record). Converting the module's procedural hooks to an OOP hook class improves structure, discoverability and testability, and aligns Varbase SEO with Drupal core.

Steps to reproduce

Proposed resolution

Move the convertible procedural hooks from varbase_seo.module into src/Hook/VarbaseSeoHooks.php with #[Hook('...')] attributes (form_node_form_alter, form_metatag_defaults_edit_form_alter, modules_installed, pathauto_punctuation_chars_alter). Install/update/schema hooks stay procedural.

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ✅ Reviewed by a human
• ✅ Code review by maintainers
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes
• ✅ Release varbase-9.2.0, varbase_seo-9.2.0

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• task: #3608315 Remove the #[LegacyHook] shims for full OOP hooks