nx_doctor_asm_fix.nx

nx_doctor_asm_fix.nx -- the DOCTOR fixes the miscompile in the MACHINE CODE, from the Engineer's artifact (which register, which call line). The fix is the textbook caller- save proven correct by the G1 allocator model (nx_regalloc_calls): a value that must survive a call is SPILLED across it. At the assembly level that is `pushq %reg` right before the offending call and `popq %reg` right after -- the call's clobber of the caller-saved register no longer matters, because the value is restored from the stack. One emit pass, milliseconds. RACI: the Doctor only PRODUCES the patched candidate; the Engineer re-verifies (re-scan + execute) and the Council admits. Depends only on syscalls -- decoupled from the Engineer. license_tier: ORIGINAL