Use MIME parsing to detect JSON script content

PR #62: Use MIME parsing to detect JSON script content

PR #62 enhances SCRIPT type attribute processing to accurately identify JSON media types, including application/json and application/ld+json. This update addresses a previously noted TODO and improves script content handling.

This update expands coverage for JSON content identification, preventing issues related to misinterpretation of script content types. New PHPUnit test cases validate detection of JSON media types, including parameters and structured suffixes. A guard filters out non-JSON lookalikes, enhancing reliability in content parsing.