feat: expose approx_mode on vector queries

`ApproxMode` landed in the Rust core in #3549, but the Python and Node.js bindings were never plumbed, so `approx_mode` is unreachable from either SDK. Both were built mirroring the existing `ef` plumbing.

Co-authored-by: Leo <leo@insight.co>

nodejs/src/query.rs

@@ -15,6 +15,7 @@ use arrow_array::{
 };
 use arrow_buffer::ScalarBuffer;
 use half::f16;
+use lancedb::ApproxMode;
 use lancedb::index::scalar::{
     BooleanQuery, BoostQuery, FtsQuery, FullTextSearchQuery, MatchQuery, MultiMatchQuery, Occur,
     Operator, PhraseQuery,
@@ -352,6 +353,13 @@ impl VectorQuery {
         self.inner = self.inner.clone().ef(ef as usize);
     }
 
+    #[napi]
+    pub fn approx_mode(&mut self, approx_mode: String) -> napi::Result<()> {
+        let approx_mode = ApproxMode::try_from(approx_mode.as_str()).default_error()?;
+        self.inner = self.inner.clone().approx_mode(approx_mode);
+        Ok(())
+    }
+
     #[napi]
     pub fn bypass_vector_index(&mut self) {
         self.inner = self.inner.clone().bypass_vector_index()