fix[faustwp]: (#2311) clean up uploaded blockset zip when extraction fails

[latenighthackathon]

Summary

When unzip_uploaded_file() returns a WP_Error in process_and_replace_blocks(), the uploaded .zip stays behind in the target directory. Repeat failures accumulate dead files.

This PR deletes the target file before returning the error so the upload slot stays clean. Mirrors the existing cleanup_temp_directory() call on the success path.

Related Issue

Closes #2311

Split out from #2312 per @josephfusco's review feedback — the hash_equals() security hardening stays on #2312 so each change can be reviewed and reverted independently.

Confirm the issue

# The success path cleans up via cleanup_temp_directory(); the error path did not.
grep -n "cleanup_temp_directory\|return \$unzip_result" plugins/faustwp/includes/blocks/functions.php
# Expected on canary (before fix):
#   54:    $unzip_result = unzip_uploaded_file( $target_file, $dirs['target'] );
#   56:        return $unzip_result;       ← no delete of $target_file
#   59:    cleanup_temp_directory( $wp_filesystem, $dirs['temp'] );

Confirm the fix

# After this PR, the error branch explicitly deletes the uploaded zip.
sed -n '54,58p' plugins/faustwp/includes/blocks/functions.php
# Expected:
#   $unzip_result = unzip_uploaded_file( $target_file, $dirs['target'] );
#   if ( is_wp_error( $unzip_result ) ) {
#       $wp_filesystem->delete( $target_file );
#       return $unzip_result;
#   }

Run the test suite

# PHPCS for the touched file
npm run phpcs --prefix plugins/faustwp -- includes/blocks/functions.php

# PHPUnit for the blocks module
npm run test:php --prefix plugins/faustwp -- --filter=Blocks

Checklist

• Targets canary
• Changeset added (@faustwp/wordpress-plugin patch)
• Commit is signed (SSH)
• Semantic commit prefix with issue reference

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[changeset-bot]

🦋 Changeset detected

Latest commit: 6295806

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@faustwp/wordpress-plugin	Patch

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