refactor(dictionary): remove unused counterId/size getters

Both methods were added to Dictionary's public surface in this PR but
have zero callers anywhere in the codebase.  Drop them; the underlying
_id and _size fields remain because they are used internally.

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

Author: jbachorik

ddprof-lib/src/main/cpp/dictionary.h

@@ -84,9 +84,6 @@ class Dictionary {
   unsigned int bounded_lookup(const char *key, size_t length, int size_limit);
 
   void collect(std::map<unsigned int, const char *> &map);
-
-  int  counterId() const { return _id; }
-  int  size() const { return _size; }
 };
 
 #endif // _DICTIONARY_H