build: Upgrade GitHub Actions for Node 24 compatibility (#56)

## Summary

Upgrade GitHub Actions to their latest versions to ensure compatibility
with Node 24, as Node 20 will reach end-of-life in April 2026.

## Changes

| Action | Old Version(s) | New Version | Release | Files |
|--------|---------------|-------------|---------|-------|
| `actions/upload-artifact` |
[`ea165f8`](actions/upload-artifact@ea165f8)
|
[`b7c566a`](actions/upload-artifact@b7c566a)
| [Release](https://github.com/actions/upload-artifact/releases/tag/v6)
| build-and-test.yml |

## Context

Per [GitHub's
announcement](https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/),
Node 20 is being deprecated and runners will begin using Node 24 by
default starting June 2nd, 2026.

### Why this matters

- **Node 20 EOL**: April 2026
- **Node 24 default**: June 2nd, 2026
- **Action**: Update to latest action versions that support Node 24

### Security Note

Actions that were previously pinned to commit SHAs remain pinned to SHAs
(updated to the latest release SHA) to maintain the security benefits of
immutable references.

### Testing

These changes only affect CI/CD workflow configurations and should not
impact application functionality. The workflows should be tested by
running them on a branch before merging.

Signed-off-by: Salman Muin Kayser Chishti <13schishti@gmail.com>

Author: salmanmkc

.github/workflows/build-and-test.yml

@@ -155,7 +155,7 @@ jobs:
           echo ${{ github.event.number }} > pr_number.txt
 
       - name: Archive coverage reports
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # ratchet:actions/upload-artifact@v4
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f  # v6.0.0
         if: always()
         with:
           name: coverage-reports