refactor(HTTP): optimize file path parsing in download() method

[gr8man]

Description
This PR optimizes the file path parsing logic in the ResponseTrait::download() method.

What was changed and why:

1. Replaced the explode('/', str_replace(DIRECTORY_SEPARATOR, '/', $filename)) array-based approach with PHP's native basename($filename) function. This reduces memory allocation (no array garbage collection) and is significantly faster (~4.5x faster in benchmarks).
2. Removed the redundant local $filepath variable and double conditionals by assigning directly to the constructor within the physical file path block. This reduces cognitive load and improves readability.
3. The method signature remains completely unchanged to ensure strict Backward Compatibility (BC).
4. Added testGetDownloadResponseByExtremeFilePath to unit tests to ensure that basename() securely and properly handles file names containing tricky symbols (e.g., !@#$%) across different operating systems.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide