Hoist max_cpus into danos (root.zig), raise it to 128, and stop reserving a static [max_cpus][16 KiB] IST array. Only the BSP's IST stack is static (needed before the allocator); each AP's is heap-allocated when it comes online. Shrinks the kernel from ~1.1 MB to ~139 KiB in ReleaseSmall.
fault-ap-df pins a #DF to an AP (its own IST must catch it); affinity checks a pinned task never migrates. onException now names the core, so an AP fault is attributed and shown contained. Both teeth-checked.
Arm the low frame (copy blob, make executable) only while a core climbs, then zero it and restore RW+NX; the frame stays reserved so cores can be re-woken. startSecondary is one re-runnable attempt; boot retries a non-responding core 3x. Validated the retry path by forcing a first-attempt failure.