Update for 0.15.x, update tracy to 0.12.4

[kcbanner]

• Update tracy to 0.12.4
• Remove usingnamespace usage
• Update build.zig

[Copilot]

Pull Request Overview

This PR modernizes the codebase to be compatible with Zig version 0.15.x by removing the deprecated usingnamespace feature and updating build configuration. The changes restructure the module to use explicit public exports instead of namespace mixing.

Key changes include:

• Refactor code organization by splitting implementations into separate modules
• Replace usingnamespace with explicit public constant assignments that conditionally select between implementations
• Update build.zig to use newer Zig 0.15.x APIs and patterns

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/ztracy.zig	Main module restructured to use explicit exports instead of usingnamespace, with conditional selection between stub and implementation
src/stub.zig	New file containing stub implementations extracted from the original tracy_stub struct
src/impl.zig	New file containing full Tracy implementations extracted from the original tracy_full struct
build.zig	Updated to use newer Zig 0.15.x build system APIs including addLibrary and createModule

Comments suppressed due to low confidence (1)

src/ztracy.zig:78

• The TracyAllocator type is not exported in the main module. This could break existing code that relies on accessing TracyAllocator through the main ztracy module.

pub const AppInfo = if (enabled) impl.AppInfo else stub.AppInfo;