refactor: 拆分 oxide_emit 为独立 emit pass crate（依赖倒置）

crates/oxide_emit/src/expr/parenthesized.rs

@@ -0,0 +1,9 @@
+use crate::{CompileCtx, Emitter};
+
+impl Emitter {
+    pub(crate) fn emit_parenthesized_expression(
+        &self, p: &oxide_parser::ParenthesizedExpression, ctx: &mut CompileCtx,
+    ) -> Result<u8, String> {
+        self.emit_expression(&p.expression, ctx)
+    }
+}