Refactor and enhance Disassembler with tests and error handling

[AlienDwarf]

Testing and Reliability Improvements:

• Added comprehensive unit tests for memory protection, trampoline allocation, disassembly/relocation, and thread enumeration in src/mem.rs, src/alloc.rs, src/disasm.rs, and src/threads.rs, respectively. These tests verify correct memory permissions, allocation behavior, instruction relocation, and thread enumeration, improving reliability and maintainability.

Instruction Relocation Enhancements:

• Refactored the Disassembler::relocate method to return a new RelocationMapping struct, which includes written length and instruction offset mappings. This enables more precise tracking and debugging of relocated instructions.
• Updated transaction logic in src/transaction.rs to store redirect maps in InlineData, allowing hooks to retain instruction offset information for better gateway and trampoline management.

API and Module Visibility Adjustments:

• Changed several modules from public to internal (mod) in src/lib.rs, and updated public exports to expose only relevant API functions and types, clarifying the library's external interface. Also added a compile-time error for non-Windows platforms.

Minor Cleanups:

• Removed the unused is_relative method from Disassembler, as its functionality is now covered by improved relocation logic.