Fix path traversal detection on Windows in validateDestinationPath

[ConnorQi01]

Summary

Two test failures on Windows caused by macOS-specific assumptions in the test suite.

Proposed Changes

Fix 1: validateDestinationPath path traversal detection (Closes #2713)

• destination.split(/[\/]+/) fails to tokenize Windows backslash paths correctly — the entire path is returned as one token, so .. is never detected
• Fix: use destination.split(path.sep) for platform-correct splitting

Fix 2: installPods enhanced environment test (Closes #2715)

• Test uses : as PATH separator (macOS convention) and runs on all platforms
• The feature itself already guards with os.platform() !== 'darwin'
• Fix: skip the test on non-macOS with this.skip()

Test Plan

• npm test: 218 passing, 0 failing, 1 pending (installPods skipped on Windows)