fix(build): select the core Zig project explicitly

Review threads live on the whole diff, not on one commit, so none are shown here - a thread's line means something in the branch's final form, and painting it into an intermediate step would put it on code it is not about.

scripts/verify-zig-core-project.tsmodified+3-2

Changes to scripts/verify-zig-core-project.ts

		@@ -1,12 +1,13 @@
1	1	import { existsSync, mkdtempSync, mkdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs'
2		-import { tmpdir } from 'node:os'
3	2	import { join, resolve } from 'node:path'
4	3	import { resolveZig } from './zig'
5	4
6	5	const source = resolve(import.meta.dir, '..')
7	6	const zig = resolveZig(source)
8	7	console.log('Tracked core project:', JSON.stringify({ file: join(source, 'packages/zig/build.zig'), exists: existsSync(join(source, 'packages/zig/build.zig')) }))
9		-const root = mkdtempSync(join(tmpdir(), 'craft-core-project-'))
	8	+// Keep the fixture on the checkout's volume. Hosted Windows keeps the
	9	+// checkout on D: and the system temporary directory/compiler cache on C:.
	10	+const root = mkdtempSync(join(source, '.zig-core-project-'))
10	11	const core = join(root, 'packages', 'zig')
11	12	try {
12	13	mkdirSync(core, { recursive: true })