hv1: early-exit at main (no plugin init); tokenizer: Stage-3 single-quote + full escapes (\/ \b \f \' \r fix); builder: route BinOp via SSOT emit_binop_to_dst; hv1 verify canary route (builder→Core); docs: phase-20.39 updates

src/tokenizer/engine.rs

@@ -149,11 +149,12 @@ impl NyashTokenizer {
             }
             Some('"') => {
                 let string_value = self.read_string()?;
-                Ok(Token::new(
-                    TokenType::STRING(string_value),
-                    start_line,
-                    start_column,
-                ))
+                Ok(Token::new(TokenType::STRING(string_value), start_line, start_column))
+            }
+            // Stage‑3: シングルクォート文字列（オプトイン）
+            Some('\'') if crate::config::env::parser_stage3() => {
+                let string_value = self.read_single_quoted_string()?;
+                Ok(Token::new(TokenType::STRING(string_value), start_line, start_column))
             }
             Some(c) if c.is_ascii_digit() => {
                 let token_type = self.read_numeric_literal()?;