v1.5.7-beta.57

From newest to oldest:

• Refactored subtitle post-processing to use shlex.split for safer subprocess invocation (fixing CWE-78) and replaced _escape with _double_quotes for cleaner variable substitution logic. 37d584a
• Enhanced error handling in Titlovi provider by raising specific exceptions for 403 Forbidden responses during login, search, and download operations. #3271 8e52bad