Format code and fix clippy warnings

[ssrlive]

• Reorder and group imports in test and source files
• Split long lines and improve code formatting
• Remove unnecessary blank lines
• Replace unnecessary map_or with is_some_and in weak pointers
• Add explicit type annotation for cast in nightly feature
• Add unsafe blocks to alloc/dealloc function calls
• Fix lifetime annotations in iterator methods
• Simplify struct and function initializations