test(fs): unskip safeDelete and safeDeleteSync tests

The 'del' module resolution issues have been resolved. The tests
now pass successfully with the vendored del wrapper in src/external/del.js
and the del 8.0.1 devDependency.

Test results:
- safeDelete: 5 tests (all passing)
- safeDeleteSync: 4 tests (all passing)
- Total: 9 previously skipped tests now running

The module resolution works correctly through the external wrapper:
src/external/del.js → require('del') → node_modules/del

Author: jdalton

test/fs.test.ts

@@ -734,10 +734,7 @@ describe('fs', () => {
     })
   })
 
-  describe.skip('safeDelete', () => {
-    // Note: These tests are skipped because they require the external 'del' module
-    // which has module resolution issues in the test environment.
-    // The functionality is covered by integration tests elsewhere.
+  describe('safeDelete', () => {
 
     it('should delete files in temp directory', async () => {
       await runWithTempDir(async tmpDir => {
@@ -812,10 +809,7 @@ describe('fs', () => {
     })
   })
 
-  describe.skip('safeDeleteSync', () => {
-    // Note: These tests are skipped because they require the external 'del' module
-    // which has module resolution issues in the test environment.
-    // The functionality is covered by integration tests elsewhere.
+  describe('safeDeleteSync', () => {
 
     it('should delete files in temp directory', async () => {
       await runWithTempDir(async tmpDir => {