feat(node): expose allowExternalBlobOutsideBases in Table.add (#4317)

## Summary

- Add `allowExternalBlobOutsideBases` to the Node `AddDataOptions` and
forward it through N-API to the Rust `AddDataBuilder`.
- Document its default and local-only external blob behavior.
- Cover URI strings and URI objects, option scoping, progress callbacks,
overwrite mode, and remote rejection.

## Validation

- `pnpm test --runInBand` (21 suites passed, 1 skipped; 908 tests
passed, 6 skipped)
- `pnpm lint-ci`
- `pnpm tsc`
- `pnpm run docs`
- `cargo fmt --all -- --check`
- `CC=clang cargo clippy --profile ci -p lancedb-nodejs --all-features
-- -D warnings`

Fixes #4267

nodejs/lancedb/table.ts

@@ -124,6 +124,17 @@ export interface AddDataOptions {
    * ```
    */
   progress: (progress: WriteProgress) => void;
+
+  /**
+   * Whether blob URIs outside registered external bases may be written.
+   *
+   * Defaults to `false`. This option is supported only for local/native
+   * tables; remote tables return an error when it is enabled. An enabled write
+   * stores the absolute URI reference without registering a base or copying
+   * the external object into the database. The object must remain accessible
+   * when the blob is read later.
+   */
+  allowExternalBlobOutsideBases?: boolean;
 }
 
 export interface UpdateOptions {
@@ -1091,7 +1102,12 @@ export class LocalTable extends Table {
           }
         }
       : undefined;
-    return await this.inner.add(buffer, mode, progress);
+    return await this.inner.add(
+      buffer,
+      mode,
+      progress,
+      options?.allowExternalBlobOutsideBases,
+    );
   }
 
   async update(