fix: correct Zig download URL format for 0.14.1+

Zig changed the download URL format starting with v0.14.1:
- Old format: zig-linux-x86_64-VERSION.tar.xz
- New format: zig-x86_64-linux-VERSION.tar.xz

Changes:
- Switch from /builds to /download endpoint
- Use correct ARCH-PLATFORM order (not PLATFORM-ARCH)
- Add comment documenting the format change

This fixes the 404 error when downloading Zig 0.15.2.

Author: sreya

.github/actions/setup-zig/action.yml

@@ -39,9 +39,10 @@ runs:
           exit 1
         fi
         
-        # Download from ziglang.org index
-        TARBALL="zig-${PLATFORM}-${ARCH}-${VERSION}.tar.xz"
-        URL="https://ziglang.org/builds/zig-${PLATFORM}-${ARCH}-${VERSION}.tar.xz"
+        # Download from ziglang.org
+        # Note: Format changed in 0.14.1+ from zig-linux-x86_64 to zig-x86_64-linux
+        TARBALL="zig-${ARCH}-${PLATFORM}-${VERSION}.tar.xz"
+        URL="https://ziglang.org/download/${VERSION}/${TARBALL}"
         
         echo "Downloading Zig ${VERSION} for ${PLATFORM}-${ARCH}..."
         curl --retry 3 --retry-delay 5 -L -o "/tmp/${TARBALL}" "${URL}"