Hakozuna HZ10-HZ12: From Ownerless Recycling to Bounded Span Reclamation

This integrated Hakozuna research preprint studies one architectural progression across HZ10, HZ11, and HZ12. HZ10 establishes route, lifecycle, and measurement boundaries; HZ11 provides an ownerless speed-first recycling baseline; and HZ12 introduces advisory ownership at cold batch and retirement boundaries to enable bounded whole-span reclamation without production per-operation diagnostic atomics. The current Japanese v0.2 draft reports bounded HZ11 synthetic and real-application evidence and an HZ12 Linux retirement-turnover result: 512 spans and 32 MiB reclaimed across eight owner generations, retirement p99 1.144 ms, and zero limbo spans. HZ8 remains the recommended balanced public allocator; this manuscript is a research study of the speed/reclaim tradeoff, not a universal tcmalloc replacement claim.