check_loop_conversion_kernels.py — Phase-3 unit tests for the ½⟨111⟩ → ⟨100⟩
loop-conversion rate kernels added to ``ReactionRates``.
Checks the 1-D ingredients owned by ReactionRates:
1. Γ_uni(n) — nonnegative; zero where ΔF ≤ 0; nonzero on some small loops;
zero on large loops (small-loop biased, Phase-2 finding).
2. φ_junc — square, in [0, φ_max], symmetric, peaks on the diagonal,
zero below n_j_min.
3. ⟨100⟩ sessile kernels — K_100_grow / K_100_shrink zero below n_loop_min and
positive above; G_100 (emission) nonnegative; k2_100 ≡ 0.
4. conversion_dF agrees with the LoopEnergetics driving force.
Run: python codes/Python_Testing/check_loop_conversion_kernels.py
