Add test cases demonstrating FBIP (Functional But In-Place) optimization:
- test_fbip_clean.lux: Basic FBIP chain (map, filter, reverse)
- test_fbip_allocs.lux: Single-owner allocation test with range/map/filter/reverse
- test_no_fbip.lux: Demonstrates shared reference forcing rc>1 path
- test_rc_comparison.lux: Comparison of FBIP vs non-FBIP allocations
All tests verify no memory leaks with the RC system.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
