feat: show tool status notifications in chat during generation

Parse SSE `status` events alongside `chunk` events and display the
status text next to the spinner while the assistant is generating.
Previously the Android app discarded all non-chunk SSE events.

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

lib/screens/chat/chat_screen.dart

@@ -89,6 +89,8 @@ class _ChatScreenState extends ConsumerState<ChatScreen> {
   Widget build(BuildContext context) {
     final messagesAsync = ref.watch(messagesProvider(widget.conversationId));
     final isStreaming = ref.watch(isStreamingProvider(widget.conversationId));
+    final streamingStatus =
+        ref.watch(streamingStatusProvider(widget.conversationId));
     final voiceState = ref.watch(voiceProvider);
 
     // Scroll when messages change.
@@ -139,8 +141,13 @@ class _ChatScreenState extends ConsumerState<ChatScreen> {
                   padding: const EdgeInsets.symmetric(
                       horizontal: 8, vertical: 12),
                   itemCount: messages.length,
-                  itemBuilder: (context, i) =>
-                      ChatMessageBubble(message: messages[i]),
+                  itemBuilder: (context, i) => ChatMessageBubble(
+                    message: messages[i],
+                    streamingStatus: (i == messages.length - 1 &&
+                            messages[i].status == 'generating')
+                        ? streamingStatus
+                        : '',
+                  ),
                 );
               },
             ),