added label syntax support and highlighting

site/src/jsMain/kotlin/HomePage.kt

@@ -77,6 +77,14 @@ fun HomePage() {
 // Create, transform, and verify — the Lyng way
 import lyng.stdlib
 
+fun findFirstPositive(list) {
+    list.forEach { 
+        if (it > 0) return@findFirstPositive it 
+    }
+    null
+}
+assertEquals(42, findFirstPositive([-1, 42, -5]))
+
 val data = 1..5 // or [1,2,3,4,5]
 val evens2 = data.filter { it % 2 == 0 }.map { it * it }
 assertEquals([4, 16], evens2)

site/src/jsTest/kotlin/LyngHighlightTest.kt

@@ -20,6 +20,22 @@ import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 class LyngHighlightTest {
+    @Test
+    fun highlightsReturnAndLabels() {
+        val md = """
+            ```lyng
+            return 42
+            break@outer null
+            return@fn val
+            ```
+        """.trimIndent()
+        val html = renderMarkdown(md)
+
+        assertTrue(html.contains("hl-kw"), "Expected keyword class for 'return': $html")
+        assertTrue(html.contains("hl-lbl") || html.contains("hl-ann"), "Expected label/annotation class for @outer/@fn: $html")
+        assertTrue(html.contains(">>>").xor(true), "Should not contain prompt marker unless expected")
+    }
+
     @Test
     fun highlightsLyngFencedBlock() {
         val md = """