ci: bump Zig to 0.14.1 so CI can build (.root_module is a 0.14 API)

[abhicris]

Bug

Every CI run since 2026-04-07 has failed on every matrix cell (test × 3 OSes, build × 3 OSes × 3 optimize modes = 12 jobs) with the exact same error:

build.zig:9:10: error: no field named 'root_module' in struct 'Build.ExecutableOptions'

Sample from the most recent run (24318456000):

• Test (ubuntu-latest) — build.zig:9:10: error: no field named 'root_module' in struct 'Build.ExecutableOptions' → exit 2
• Test (macos-latest) — same error
• Test (windows-latest) — same error
• Build (ubuntu-latest, ReleaseFast/ReleaseSmall/Debug) — same error
• Build (macos-latest, *) / Build (windows-latest, *) — same error

Root cause

build.zig uses the 0.14 build-system API throughout:

Call	0.14 API used
b.addExecutable(.{ .root_module = b.createModule(...) })	7 call sites
b.addLibrary(.{ .linkage = ..., .root_module = ... })	2 call sites
b.addTest(.{ .root_module = b.createModule(...) })	1 call site

All three of these APIs were introduced in Zig 0.14.0. The .root_module field was added to Build.ExecutableOptions / Build.LibraryOptions / Build.TestOptions as part of the 0.14.0 build-system unification (replacing the old root_source_file / addSharedLibrary / addStaticLibrary family).

.github/workflows/ci.yml pins ZIG_VERSION: "0.13.0", which doesn't know about root_module. The toolchain rejects build.zig on line 9 before anything can build.

Fix

One-line change: bump ZIG_VERSION in .github/workflows/ci.yml from "0.13.0" → "0.14.1" (latest 0.14.x patch, final 0.14 release). Added a comment above the pin explaining why 0.14 specifically so future bumps don't accidentally regress to 0.13.

No source files touched. build.zig already targets 0.14; this PR just makes the CI toolchain match.

Why not bump to 0.15?

• 0.15 introduced further build-system breaking changes (notably addModule replacing some createModule patterns). Bumping past the matching major would require editing build.zig to match. Keeping the bump to 0.14.1 minimizes the blast radius — the same API build.zig already targets.
• If the repo wants to move to 0.15+ later, that's a separate follow-up PR with the build.zig migration bundled together.

Verification

Cannot verify locally (no 0.14.1 toolchain on this box), but the fix is mechanical: build.zig uses 0.14 API, so the toolchain has to be 0.14.x. This PR's own CI run will demonstrate — once GitHub picks it up, all 12 matrix cells that were failing on 0.13 should now proceed past build.zig parsing.

— kcolbchain / Abhishek Krishna