test(ffi): update kind_from_u8 out-of-range boundary 105→113

Test hardcoded the upper bound at 105, but commit c8c0acf added 8 new
ProverKind variants (CubicalAgda, Zipperposition, Prover9, OpenSMT,
SmtRat, Rocq, UppaalStratego, MizAR) so 105 is now valid. Update the
boundary to 113 (= 113-variant enum) + add a comment citing the
variant-adding commit so the next boundary move is traceable.

Fix caught by full-repo audit 2026-04-24.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

src/rust/ffi/mod.rs

@@ -1410,8 +1410,11 @@ mod tests {
 
     #[test]
     fn test_kind_from_u8_out_of_range() {
-        // 0–104 are valid; 105+ are out of range.
-        assert!(kind_from_u8(105).is_none());
+        // 0–112 are valid; 113+ are out of range.
+        // (Boundary moved 104→112 in commit c8c0acf which added 8 new ProverKind
+        //  variants: CubicalAgda, Zipperposition, Prover9, OpenSMT, SmtRat,
+        //  Rocq, UppaalStratego, MizAR.)
+        assert!(kind_from_u8(113).is_none());
         assert!(kind_from_u8(128).is_none());
         assert!(kind_from_u8(255).is_none());
     }