Upgrade to Zig 0.15.1

[hazeycode]

No description provided.

[Srekel]

Thank you! This is the migration part I find least... enticing 😅 also not sure when we will upgrade to zig 0.15.

If this is done I'm happy to merge!

[Copilot]

Pull Request Overview

This PR upgrades the codebase from Zig 0.14.0 to Zig 0.15.1, updating function calling conventions and build system configuration to align with the newer Zig version.

Key changes include:

• Updated calling convention syntax from .C to .c throughout function type definitions
• Modified build system to use new module and library creation patterns
• Fixed memory alignment API calls and function parameter ordering

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/zflecs.zig	Updated calling conventions, fixed alignment API usage, and corrected function parameter order
src/tests.zig	Updated calling conventions and simplified test struct implementation
build.zig.zon	Bumped minimum Zig version requirement to 0.15.1
build.zig	Refactored build system to use new module and library creation APIs

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[hazeycode]

Should be good now. I havn't tested in a real example but the tests are passing so I'll mark this as "ready" on that basis.

[Srekel]

Works for me! We will test it once we upgrade Tides :)