feat(ci/docs): add PHP 8.4 support to CI and docs

[KingPin]

Summary

This PR adds active support for PHP 8.4 across CI and documentation. It updates both the build-and-test and publish matrices and the README's supported images table so 8.4 is treated as an actively built, tested, and published version.

---

Changes

• CI
  • .github/workflows/docker-ci.yml: add 8.4 to php-version for both build-and-test and publish matrices (now: ['8.4','8.3','8.2']).
  • Simplified publish php-base to alpine and bookworm for consistency.
• Docs
  • README.md: added rows for PHP 8.4 in the "Current Supported Images" table (CLI, FPM, and Apache Bookworm).

---

Rationale

• PHP 8.4 is stable and provides performance/security improvements we want to offer to users.
• Adding 8.4 centralizes officially supported images and gives users an upgrade path beyond 8.3.

Testing & Verification

• Local smoke tests used during development (via test-build.sh).
• CI matrix updated; this branch adds the 8.4 combinations to PR builds and to the main-only publish job.

Impact

• CI matrix size increased; expect more CI minutes for PRs and publish runs.
• Publish behavior: Apache images are only published for Bookworm (apache+alpine remains excluded).

Rollback

• Revert this PR to remove 8.4 from matrices and README.

Follow-ups (optional)

• Limit PR job count by using selective testing or caching strategies if CI minutes become a concern.
• Add Apache test coverage to build-and-test if you want pre-publish validation for Apache/Bookworm images.

---

Please review and merge when ready.

[Copilot]

Pull Request Overview

This PR adds PHP 8.4 support to the project's CI/CD pipeline and documentation. PHP 8.4 images will now be built, tested, and published alongside existing 8.3 and 8.2 versions.

Key Changes:

• Updated CI workflows to include PHP 8.4 in both build-and-test and publish job matrices
• Added PHP 8.4 image variants to the supported images documentation table

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
.github/workflows/docker-ci.yml	Added 8.4 to php-version arrays in both build-and-test and publish job matrices
README.md	Added documentation rows for all PHP 8.4 image variants (CLI, FPM, Apache on Alpine/Bookworm)

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Pull Request Overview

Copilot reviewed 8 out of 9 changed files in this pull request and generated no new comments.

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}