nx_budget_alloc_test.nx

nx_budget_alloc_test.nx -- smoke for sovereign ceiling enforcement. Exercises: 1. Allocations within budget succeed; ram_used increments correctly 2. Allocation that WOULD exceed ceiling returns NULL; ram_used unchanged (refusal BEFORE sys_mmap) 3. Verdict-returning variant distinguishes OVER vs BAD_KIND vs OK 4. release_logical decrements ram_used; subsequent allocations succeed up to fresh headroom 5. Multiple kinds enforce independently (RAM ceiling does not block VRAM allocation and vice versa) 6. Bad-input gates: null budget, zero size, negative size 7. Sealed-enum verdict gate 8. headroom() reflects state across allocations + releases Pure substrate: no /sys/fs/cgroup, no kernel cgroups, no Linux- only assumptions. Same code path runs on every host.