Add syntax highlighting infrastructure

- Introduced `HighlighterRegistry` with support for multiple language highlighters (e.g., JSON, Markdown, Python).
- Added `JsonHighlighter` implementation for basic JSON syntax highlighting.

GUIConfig.cc

@@ -102,17 +102,27 @@ GUIConfig::LoadFromFile(const std::string &path)
 			if (v > 0.0f) {
 				font_size = v;
 			}
-		} else if (key == "theme") {
-			theme = val;
-		} else if (key == "background" || key == "bg") {
-			std::string v = val;
-			std::transform(v.begin(), v.end(), v.begin(), [](unsigned char c) {
-				return (char) std::tolower(c);
-			});
-			if (v == "light" || v == "dark")
-				background = v;
-		}
-	}
+        } else if (key == "theme") {
+            theme = val;
+        } else if (key == "background" || key == "bg") {
+            std::string v = val;
+            std::transform(v.begin(), v.end(), v.begin(), [](unsigned char c) {
+                return (char) std::tolower(c);
+            });
+            if (v == "light" || v == "dark")
+                background = v;
+        } else if (key == "syntax") {
+            std::string v = val;
+            std::transform(v.begin(), v.end(), v.begin(), [](unsigned char c) {
+                return (char) std::tolower(c);
+            });
+            if (v == "1" || v == "on" || v == "true" || v == "yes") {
+                syntax = true;
+            } else if (v == "0" || v == "off" || v == "false" || v == "no") {
+                syntax = false;
+            }
+        }
+    }
 
-	return true;
+    return true;
 }