docs(nodejs): clarify Table.add progress dispatch semantics

docs/src/js/interfaces/AddDataOptions.md

@@ -31,9 +31,9 @@ progress: (progress) => void;
 Optional callback invoked periodically with write progress.
 
 The callback is fired once per batch written and once more with
-`done: true` when the write completes. Calls are non-blocking — if the
-callback is slow, intermediate updates may be dropped to avoid stalling
-the write.
+`done: true` when the write completes. Calls are dispatched
+asynchronously to the JS event loop and never block the write — a slow
+callback will queue events rather than back-pressure the writer.
 
 Errors thrown from the callback are logged with `console.warn` and
 swallowed — they do not abort the write.

nodejs/lancedb/table.ts

@@ -88,9 +88,9 @@ export interface AddDataOptions {
    * Optional callback invoked periodically with write progress.
    *
    * The callback is fired once per batch written and once more with
-   * `done: true` when the write completes. Calls are non-blocking — if the
-   * callback is slow, intermediate updates may be dropped to avoid stalling
-   * the write.
+   * `done: true` when the write completes. Calls are dispatched
+   * asynchronously to the JS event loop and never block the write — a slow
+   * callback will queue events rather than back-pressure the writer.
    *
    * Errors thrown from the callback are logged with `console.warn` and
    * swallowed — they do not abort the write.

nodejs/src/table.rs

@@ -103,8 +103,10 @@ impl Table {
 
         if let Some(tsfn) = progress_callback {
             op = op.progress(move |p| {
-                // Non-blocking: drop progress events rather than back-pressuring
-                // the write if the JS callback can't keep up.
+                // NonBlocking: dispatch onto the JS event loop without
+                // blocking the writer thread.  With napi-rs's default
+                // unbounded queue, events are not dropped — a slow JS
+                // callback will just queue them.
                 tsfn.call(
                     WriteProgressInfo::from(p),
                     ThreadsafeFunctionCallMode::NonBlocking,