fix(node): route auto search using table embeddings (#3832)

## Summary

- Resolve automatic string-search routing from the active table schema
whenever the query executes.
- Defer embedding-provider construction while leaving explicit vector
and FTS routes unchanged.
- Cover unrelated global registrations and metadata transitions across
repeated executions of one query builder.

## Root cause

LocalTable.search used the number of globally registered embedding
providers to choose between vector and full-text search. A provider
registered for any other table therefore sent a plain FTS table down the
vector path. A wrapper-lifetime metadata snapshot avoided that
contamination but became stale after time travel or read-consistency
refreshes. The query now records fluent builder operations and creates
the appropriate native vector or FTS query from the active schema on
each execution.

## Validation

- pnpm build
- pnpm tsc
- pnpm lint
- pnpm run docs
- pnpm test --runInBand (681 passed, 5 skipped)

Fixes #1557

<!-- lance-gatekeeper-fix:v1 agent=b6183df8296db4aabdc5d19a2256b029
generation=1 -->

---------

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
Co-authored-by: Xuanwo <github@xuanwo.io>

nodejs/src/table.rs

@@ -278,6 +278,13 @@ impl Table {
         Ok(Query::new(self.inner_ref()?.query()))
     }
 
+    /// Return a read-only table handle pinned to the current query revision.
+    #[napi(catch_unwind)]
+    pub async fn query_snapshot(&self) -> napi::Result<Self> {
+        let snapshot = self.inner_ref()?.query_snapshot().await.default_error()?;
+        Ok(Self::new(snapshot))
+    }
+
     #[napi(catch_unwind)]
     pub fn take_offsets(&self, offsets: Vec<i64>) -> napi::Result<TakeQuery> {
         Ok(TakeQuery::new(