Adapt for Zig 0.17

[wrench1997]

This PR updates zphysics for Zig 0.17 compatibility:

Changes:

• Update @typeinfo struct field iteration (field_names/field_types arrays)
• Replace @cImport with addTranslateC in build.zig
• Replace std.Thread.Mutex with std.Io.Mutex (removed in 0.17)
• Update test initialization to use std.Io.Threaded
• Add @aligncast where needed for pointer conversions
• Change AllowedDOFs from enum to packed struct(u8) for C ABI compatibility
• Fix struct layouts with explicit padding to match C ABI
• Add helper methods for accessing u8-backed arrays as f32 arrays
• Add size analysis and testing tools

Testing Environment:

• OS: Windows 10 Pro
• Zig: 0.17.0-dev.892+54537285c
• Compiler: MSVC (JoltC)