fix: resolve linting errors in cross-platform test utilities

- Replace any type with unknown in createConditionalTest function
- Remove unused shouldSkipTest import from test file
- Ensure all linting rules pass for cross-platform testing code

Author: Mearman

src/utils/test-helpers.test.ts

@@ -7,7 +7,6 @@ import {
   convertPathSeparators,
   wouldFilenamesConflict,
   skipIfUnsupported,
-  shouldSkipTest,
   createConditionalTest,
   fileExists,
   getTestPaths,

src/utils/test-helpers.ts

@@ -187,7 +187,7 @@ export function shouldSkipTest(
  * Create test helper that conditionally runs based on platform capabilities
  * Note: This function expects to be called within a test context where `test` is available
  */
-export function createConditionalTest(testFn: any) {
+export function createConditionalTest(testFn: unknown) {
   return function conditionalTest(
     name: string,
     requirement: 'symlinks' | 'case-sensitivity' | 'windows' | 'unix',