vMLX 1.6.17

Public runtime and packaging checkpoint. Includes reasoning/content streaming hardening, KaTeX renderer fixes, model-derived defaults, parser/tool-loop fixes, typed cache/L2 restore work across representative families, and recursive Developer ID signing for all bundled Mach-O leaves. Exact source: d03ec29. Broader family/media/eviction/soak rows remain documented follow-up work.