fix(react-hooks): prevent onComplete from firing prematurely when stream disconnects (#2929)

## Summary

Fixes #2856 - The `onComplete` callback in `useRealtimeRun` was firing prematurely

## Root Cause

The callback was triggered when the long-poll stream ended, regardless
of whether the run had actually completed. Reverse proxies often close
idle connections, causing the stream to end prematurely. In this case it
was caused by fetch abort due to React strict mode.

## Fix

Changed the condition from checking if `run` exists to checking if
`run?.finishedAt` exists, ensuring `onComplete` only fires when the run
has reached a terminal state.

---------

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: nicktrn <nicktrn@users.noreply.github.com>

Author: nicktrn

.changeset/calm-hooks-wait.md

@@ -0,0 +1,5 @@
+---
+"@trigger.dev/react-hooks": patch
+---
+
+Fix `onComplete` callback firing prematurely when the realtime stream disconnects before the run finishes.

packages/react-hooks/src/hooks/useRealtime.ts

@@ -149,8 +149,10 @@ export function useRealtimeRun<TTask extends AnyTask>(
   const hasCalledOnCompleteRef = useRef(false);
 
   // Effect to handle onComplete callback
+  // Only call onComplete when the run has actually finished (has finishedAt),
+  // not just when the subscription stream ends (which can happen due to network issues)
   useEffect(() => {
-    if (isComplete && run && options?.onComplete && !hasCalledOnCompleteRef.current) {
+    if (isComplete && run?.finishedAt && options?.onComplete && !hasCalledOnCompleteRef.current) {
       options.onComplete(run, error);
       hasCalledOnCompleteRef.current = true;
     }
@@ -313,8 +315,10 @@ export function useRealtimeRunWithStreams<
   const hasCalledOnCompleteRef = useRef(false);
 
   // Effect to handle onComplete callback
+  // Only call onComplete when the run has actually finished (has finishedAt),
+  // not just when the subscription stream ends (which can happen due to network issues)
   useEffect(() => {
-    if (isComplete && run && options?.onComplete && !hasCalledOnCompleteRef.current) {
+    if (isComplete && run?.finishedAt && options?.onComplete && !hasCalledOnCompleteRef.current) {
       options.onComplete(run, error);
       hasCalledOnCompleteRef.current = true;
     }