mlx-native 0.15.6

What's Changed

• test(perf): stabilize M5 chunk-o warmup without changing its speed bar by @robertelee78 in #62
• feat(memory): enforce opt-in live and pending requested-root limits by @robertelee78 in #61
• chore(release): prepare mlx-native 0.15.6 by @robertelee78 in #63

Full Changelog: v0.15.5...v0.15.6