fix: remove .lance-reserved marker after writing table in namespace mode

lance v6.0.0-beta.2 introduced a `.lance-reserved` marker file in
declare_table to prevent directory scans from seeing incomplete tables.
lancedb calls declare_table to get the canonical URI, then writes data
separately via NativeTable::create_from_namespace, but never cleaned up
the marker. This caused list_directory_tables() to skip tables with the
marker, making newly created tables invisible in table_names().

After writing the table, delete the marker using the dataset's configured
object store so it works for both local and cloud storage.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

rust/lancedb/src/database/namespace.rs

@@ -8,7 +8,9 @@ use std::sync::Arc;
 
 use async_trait::async_trait;
 use lance::io::commit::namespace_manifest::LanceNamespaceExternalManifestStore;
-use lance_io::object_store::{ObjectStoreParams, StorageOptionsAccessor};
+use lance_io::object_store::{
+    ObjectStore as LanceObjectStore, ObjectStoreParams, ObjectStoreRegistry, StorageOptionsAccessor,
+};
 use lance_namespace::{
     LanceNamespace,
     models::{
@@ -341,6 +343,20 @@ impl Database for LanceNamespaceDatabase {
         )
         .await?;
 
+        // lance >= v6.0.0-beta.2: declare_table creates a `.lance-reserved` marker file to
+        // prevent directory scanning from seeing an incomplete table. After writing data we
+        // must remove it so the table appears in directory listings.
+        if let Ok(dataset) = native_table.dataset.get().await {
+            let registry = Arc::new(ObjectStoreRegistry::default());
+            if let Ok(table_path) = LanceObjectStore::extract_path_from_uri(registry, dataset.uri())
+            {
+                let _ = dataset
+                    .object_store
+                    .delete(&table_path.child(".lance-reserved"))
+                    .await;
+            }
+        }
+
         Ok(Arc::new(native_table))
     }