Improve red-black tree map implementation

* Single allocation per node (54% memory reduction)
* Eliminate double traversal in insert (3-4x faster)
* Comprehensive error handling and overflow protection
* Improve test suite
  - Red-black tree property validation
  - Memory stress testing (100K elements)
  - Edge case coverage

Author: jserv

src/breakpoint.c

@@ -12,7 +12,9 @@
 static inline int cmp(const void *arg0, const void *arg1)
 {
     riscv_word_t *a = (riscv_word_t *) arg0, *b = (riscv_word_t *) arg1;
-    return (*a < *b) ? _CMP_LESS : (*a > *b) ? _CMP_GREATER : _CMP_EQUAL;
+    return (*a < *b)   ? MAP_CMP_LESS
+           : (*a > *b) ? MAP_CMP_GREATER
+                       : MAP_CMP_EQUAL;
 }
 
 breakpoint_map_t breakpoint_map_new()