Replace the single-pass body run with table-2-slg-iter / table-3-slg-iter:
each iteration stores the current vals in cache and re-runs the body;
loop until vals length stops growing. The cache thus grows
monotonically until no new answers appear.
For simple cycles (single tabled relation) this is sound and
terminating — len comparison is O(1) and the cache only grows.
Limitation: mutually-recursive tabled relations have INDEPENDENT
iteration loops. Each runs to its own fixed point in isolation; the
two don't coordinate. True SLG uses a worklist that cross-fires
re-iteration when any subgoal's cache grows. Left as a future
refinement.
All 5 SLG tests still pass (Fibonacci unchanged, 3 cyclic-patho
cases unchanged).