fix(sandbox): reject overlapping Windows temp roots

packages/sandbox/sandbox-windows-acl/tests/path-boundary.spec.ts

@@ -0,0 +1,53 @@
+/** Canonical path-overlap checks that keep workspace and temp capabilities separate. */
+
+import { mkdirSync, mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, describe, expect, it } from 'vitest'
+
+import { assertPrivateTempDisjoint, assertTempRootOutsideWorkspace } from '../src/path-boundary.ts'
+
+describe('Windows ACL temp path boundary', () => {
+  const scratchDirs: string[] = []
+
+  afterEach(() => {
+    for (const dir of scratchDirs.splice(0)) rmSync(dir, { recursive: true, force: true })
+  })
+
+  function scratch(): string {
+    const dir = mkdtempSync(join(tmpdir(), 'dsh-acl-boundary-'))
+    scratchDirs.push(dir)
+    return dir
+  }
+
+  it('rejects a temp root equal to or below the workspace', () => {
+    const workspace = scratch()
+    const nested = join(workspace, 'temp')
+    mkdirSync(nested)
+
+    expect(() => assertTempRootOutsideWorkspace(workspace, workspace)).toThrow(/temp root must be outside the workspace/u)
+    expect(() => assertTempRootOutsideWorkspace(workspace, nested)).toThrow(/temp root must be outside the workspace/u)
+  })
+
+  it('accepts a temp parent above the workspace because a fresh child is a sibling', () => {
+    const tempRoot = scratch()
+    const workspace = join(tempRoot, 'workspace')
+    mkdirSync(workspace)
+
+    expect(() => assertTempRootOutsideWorkspace(workspace, tempRoot)).not.toThrow()
+  })
+
+  it('requires an actual private temp directory to be disjoint in either direction', () => {
+    const root = scratch()
+    const workspace = join(root, 'workspace')
+    const nestedTemp = join(workspace, 'temp')
+    const siblingTemp = join(root, 'sibling-temp')
+    mkdirSync(workspace)
+    mkdirSync(nestedTemp)
+    mkdirSync(siblingTemp)
+
+    expect(() => assertPrivateTempDisjoint([workspace], nestedTemp)).toThrow(/must be disjoint/u)
+    expect(() => assertPrivateTempDisjoint([nestedTemp], workspace)).toThrow(/must be disjoint/u)
+    expect(() => assertPrivateTempDisjoint([workspace], siblingTemp)).not.toThrow()
+  })
+})