Add memory usage comparison script

- Create memory_compare.py to measure peak RSS across implementations
- Uses /usr/bin/time on Linux/macOS to measure peak memory
- Creates temporary Swift package for memory measurement
- Generates MEMORY_RESULTS.md report with comparison table
- Add MEMORY_RESULTS.md to .gitignore (generated output)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: kylehowells

.gitignore

@@ -34,3 +34,4 @@ fastlane/test_output
 Benchmarks/samples/
 Benchmarks/*.json
 Benchmarks/test_files/synthetic.html
+Benchmarks/MEMORY_RESULTS.md