Add configuration option for ghost reset distance. Improve documentation.

config.h

@@ -4,8 +4,10 @@
 #include <string>
 #include <map>
 
+// Config is a minimal line-oriented JSON reader used to expose tuning knobs at runtime.
 class Config {
 public:
+    // Reads the file into a flat string map; best-effort, tolerates missing files.
     static bool loadFromFile(const std::string& filename);
     static float getFloat(const std::string& key, float defaultValue);
     static int getInt(const std::string& key, int defaultValue);
@@ -17,4 +19,4 @@ private:
     static bool parseJsonValue(const std::string& line, std::string& key, std::string& value);
 };
 
-#endif
+#endif