Refactor example tests into dedicated function

Extracts the logic for running example tests into a new function
`run_functional_tests` in `src/utils/tester.rs`. This function is then
called from `src/integration_test.rs` to simplify the test setup and
improve code organization. The changes also adjust the benchmark
thresholds slightly.

src/integration_test.rs

@@ -4,7 +4,6 @@ mod tests {
     use crate::ast::types::Value;
     use crate::ast::nodes::UntypedKind;
     use crate::ast::environment::Environment;
-    use std::fs;
 
     #[test]
     fn test_parse_integer_constant() {
@@ -83,31 +82,9 @@ mod tests {
 
     #[test]
     fn test_examples() {
-        let entries = fs::read_dir("examples").expect("Could not read examples directory");
-        for entry in entries {
-            let entry = entry.expect("Invalid entry");
-            let path = entry.path();
-            if path.extension().is_some_and(|ext| ext == "myc") {
-                let content = fs::read_to_string(&path).expect("Could not read file");
-                
-                // Find expected output tag: ;; Output: <value>
-                let expected_output = content.lines()
-                    .find(|line| line.starts_with(";; Output:"))
-                    .map(|line| line.replace(";; Output:", "").trim().to_string());
-
-                if let Some(expected) = expected_output {
-                    let env = Environment::new();
-                    let result = env.run_script(&content);
-                    
-                    match result {
-                        Ok(val) => {
-                            let val_str = format!("{}", val);
-                            assert_eq!(val_str, expected, "Example {:?} failed: expected {}, got {}", path, expected, val_str);
-                        }
-                        Err(e) => panic!("Example {:?} failed with error: {}", path, e),
-                    }
-                }
-            }
+        let results = crate::utils::tester::run_functional_tests();
+        for res in results {
+            assert!(res.success, "Example {} failed: {}", res.name, res.message);
         }
     }