fix(Rosenbrock): add strip_cache override for RosenbrockCache

RosenbrockCache contains concrete container fields (Vector, Matrix, Int)
which cannot accept , causing generic strip_cache to fail.

Add specialized strip_cache that clears arrays and nulls AD/interp fields
while preserving required structure.

Fixes InterfaceI strip tests.

Author: Harsh Singh

lib/OrdinaryDiffEqRosenbrock/src/interp_func.jl

@@ -27,3 +27,40 @@ function SciMLBase.interp_summary(
         "specialized 4th (Rodas6P = 5th) order \"free\" stiffness-aware interpolation" :
         "1st order linear"
 end
+
+# RosenbrockCache has concrete container fields (Vector{rateType}, Matrix{tabType}, Int)
+# that cannot accept `nothing`, so the generic strip_cache (which passes all `nothing`) fails.
+# This override clears arrays to empty versions while preserving type stability.
+function OrdinaryDiffEqCore.strip_cache(cache::RosenbrockCache)
+    return RosenbrockCache(
+        cache.u,
+        cache.uprev,
+        similar(cache.dense, 0),
+        cache.du,
+        cache.du1,
+        cache.du2,
+        similar(cache.dtC, 0, 0),
+        similar(cache.dtd, 0),
+        similar(cache.ks, 0),
+        cache.fsalfirst,
+        cache.fsallast,
+        cache.dT,
+        cache.J,
+        cache.W,
+        cache.tmp,
+        cache.atmp,
+        cache.weight,
+        cache.tab,
+        nothing,
+        nothing,
+        cache.linsolve_tmp,
+        cache.linsolve,
+        nothing,
+        nothing,
+        cache.reltol,
+        cache.alg,
+        cache.step_limiter!,
+        cache.stage_limiter!,
+        cache.interp_order
+    )
+end