feat(boot): add -ROT <= >= gforth extensions

Non-standard but ubiquitous words; absence aborted otherwise-valid
gforth programs with unknown-word errors.

crates/core/boot.fth

@@ -72,6 +72,19 @@
     1-
   REPEAT ;
 
+\ ---------------------------------------------------------------
+\ Common extensions (not in Forth 2012, gforth-compatible)
+\ ---------------------------------------------------------------
+
+\ -ROT ( x1 x2 x3 -- x3 x1 x2 )  rotate top item to third place
+: -ROT  ROT ROT ;
+
+\ <= ( n1 n2 -- flag )  true if n1 <= n2 (signed)
+: <=  > 0= ;
+
+\ >= ( n1 n2 -- flag )  true if n1 >= n2 (signed)
+: >=  < 0= ;
+
 \ ---------------------------------------------------------------
 \ Phase 2: Double-cell arithmetic
 \ ---------------------------------------------------------------

crates/core/src/outer.rs

@@ -7462,6 +7462,12 @@ mod tests {
         assert_eq!(eval_stack("1 2 3 ROT"), vec![1, 3, 2]);
     }
 
+    #[test]
+    fn test_minus_rot() {
+        // ( 1 2 3 -- 3 1 2 )  top-first: [2, 1, 3]
+        assert_eq!(eval_stack("1 2 3 -ROT"), vec![2, 1, 3]);
+    }
+
     // -- Comparison --
 
     #[test]
@@ -7482,6 +7488,20 @@ mod tests {
         assert_eq!(eval_stack("3 5 >"), vec![0]);
     }
 
+    #[test]
+    fn test_less_or_equal() {
+        assert_eq!(eval_stack("3 5 <="), vec![-1]);
+        assert_eq!(eval_stack("5 5 <="), vec![-1]);
+        assert_eq!(eval_stack("5 3 <="), vec![0]);
+    }
+
+    #[test]
+    fn test_greater_or_equal() {
+        assert_eq!(eval_stack("5 3 >="), vec![-1]);
+        assert_eq!(eval_stack("5 5 >="), vec![-1]);
+        assert_eq!(eval_stack("3 5 >="), vec![0]);
+    }
+
     // -- Logic --
 
     #[test]