feat(lexer): Comments

tests/lexer/LexerScanTest.kt

@@ -167,4 +167,27 @@ class LexerScanTest {
 
         assertEquals("string with space", tokens[0].value, "Expected 'string with space', got ${tokens[0].value}")
     }
+
+    @Test
+    fun scan_comments_returns_nothing() {
+        val lexer = Lexer("% comment")
+        val tokens = lexer.scan()
+
+        assertEquals(1, tokens.size)
+
+        assertEquals(TokenType.EOF, tokens[0].type, "Expected EOF token, got ${tokens[0].type}")
+    }
+
+    @Test
+    fun scan_comment_and_sentence_returns_sentence() {
+        val tokens = Lexer("""
+            % comment
+            sentence
+        """.trimIndent()).scan()
+
+        assertEquals(2, tokens.size)
+
+        assertEquals(TokenType.ALPHANUMERIC, tokens[0].type, "Expected ALPHANUMERIC token, got ${tokens[0].type}")
+        assertEquals("sentence", tokens[0].value, "Expected 'sentence', got ${tokens[0].value}")
+    }
 }