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/providers/briefing_provider.dart

@@ -1,5 +1,6 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import '../data/api/chat_api.dart';
 import '../data/models/briefing_conversation.dart';
 import '../data/models/message.dart';
 import 'api_client_provider.dart';
@@ -48,6 +49,86 @@ class BriefingNotifier extends AsyncNotifier<BriefingConversation> {
     await future;
   }
 
+  /// Inject a news article as context and trigger generation.
+  ///
+  /// Mirrors sendReply() but calls the /discuss endpoint instead of
+  /// /messages so the backend injects article content before generating.
+  Future<void> discussArticle(int convId, int itemId) async {
+    final conv = state.value;
+    if (conv == null) return;
+    final chatApi = ref.read(chatApiProvider);
+    final briefingApi = ref.read(briefingApiProvider);
+
+    final previous = conv.messages;
+    final placeholder = Message(
+      conversationId: convId,
+      role: MessageRole.assistant,
+      content: '',
+      status: 'generating',
+    );
+    state = AsyncData(conv.copyWith(messages: [...previous, placeholder]));
+    ref.read(isBriefingStreamingProvider.notifier).state = true;
+
+    try {
+      await briefingApi.discussArticle(convId, itemId);
+    } catch (e) {
+      state = AsyncData(conv.copyWith(messages: previous));
+      ref.read(isBriefingStreamingProvider.notifier).state = false;
+      rethrow;
+    }
+
+    // SSE stream (best-effort)
+    bool streamedContent = false;
+    try {
+      await for (final event in chatApi.streamGeneration(convId)) {
+        if (event is! ChatTextChunk) continue;
+        streamedContent = true;
+        final current = state.value;
+        if (current == null) break;
+        final msgs = current.messages;
+        if (msgs.isEmpty) continue;
+        final updated =
+            msgs.last.copyWith(content: msgs.last.content + event.text);
+        state = AsyncData(current.copyWith(
+            messages: [...msgs.sublist(0, msgs.length - 1), updated]));
+      }
+    } catch (_) {
+      // Fall through to polling.
+    }
+
+    // Poll until complete (max 20 attempts, 2s apart)
+    try {
+      for (var attempt = 0; attempt < 20; attempt++) {
+        if (attempt > 0) await Future.delayed(const Duration(seconds: 2));
+        final fresh = await briefingApi.getMessages(convId);
+        final done = fresh.any(
+          (m) => m.role == MessageRole.assistant && m.status != 'generating',
+        );
+        final hasContent = fresh.any(
+          (m) => m.role == MessageRole.assistant && m.content.isNotEmpty,
+        );
+        final current = state.value;
+        if (current != null && (!streamedContent || done || hasContent)) {
+          state = AsyncData(current.copyWith(messages: fresh));
+        }
+        if (done) break;
+      }
+    } catch (_) {
+      final current = state.value;
+      if (current != null) {
+        final msgs = current.messages;
+        if (msgs.isNotEmpty && msgs.last.status == 'generating') {
+          state = AsyncData(current.copyWith(messages: [
+            ...msgs.sublist(0, msgs.length - 1),
+            msgs.last.copyWith(status: 'complete'),
+          ]));
+        }
+      }
+    } finally {
+      ref.read(isBriefingStreamingProvider.notifier).state = false;
+    }
+  }
+
   /// Send a reply to today's briefing conversation.
   ///
   /// Mirrors MessagesNotifier.sendMessage():
@@ -87,13 +168,15 @@ class BriefingNotifier extends AsyncNotifier<BriefingConversation> {
     // SSE stream (best-effort)
     bool streamedContent = false;
     try {
-      await for (final chunk in chatApi.streamGeneration(convId)) {
+      await for (final event in chatApi.streamGeneration(convId)) {
+        if (event is! ChatTextChunk) continue;
         streamedContent = true;
         final current = state.value;
         if (current == null) break;
         final msgs = current.messages;
         if (msgs.isEmpty) continue;
-        final updated = msgs.last.copyWith(content: msgs.last.content + chunk);
+        final updated =
+            msgs.last.copyWith(content: msgs.last.content + event.text);
         state = AsyncData(current.copyWith(
             messages: [...msgs.sublist(0, msgs.length - 1), updated]));
       }

lib/providers/chat_provider.dart

@@ -2,6 +2,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../data/models/conversation.dart';
 import '../data/models/message.dart';
+import '../data/repositories/chat_repository.dart';
 import 'api_client_provider.dart';
 
 // Separate NotifierProvider.family so UI re-builds immediately when streaming starts/stops.
@@ -18,6 +19,20 @@ class _IsStreamingNotifier extends Notifier<bool> {
   bool build() => false;
 }
 
+// Tracks the current tool status text during generation (empty = no status).
+final streamingStatusProvider =
+    NotifierProvider.family<_StreamingStatusNotifier, String, int>(
+  (convId) => _StreamingStatusNotifier(convId),
+);
+
+class _StreamingStatusNotifier extends Notifier<String> {
+  // ignore: avoid_unused_constructor_parameters
+  _StreamingStatusNotifier(int convId);
+
+  @override
+  String build() => '';
+}
+
 final conversationsProvider =
     AsyncNotifierProvider<ConversationsNotifier, List<Conversation>>(
         ConversationsNotifier.new);
@@ -103,12 +118,19 @@ class MessagesNotifier extends AsyncNotifier<List<Message>> {
     // ── Step 2: Stream the response (best effort — silent on failure). ──
     bool streamedContent = false;
     try {
-      await for (final chunk in repo.streamGeneration(convId)) {
-        streamedContent = true;
-        final msgs = state.requireValue;
-        if (msgs.isEmpty) continue;
-        final updated = msgs.last.copyWith(content: msgs.last.content + chunk);
-        state = AsyncData([...msgs.sublist(0, msgs.length - 1), updated]);
+      await for (final event in repo.streamGeneration(convId)) {
+        if (event is ChatTextChunk) {
+          streamedContent = true;
+          ref.read(streamingStatusProvider(convId).notifier).state = '';
+          final msgs = state.requireValue;
+          if (msgs.isEmpty) continue;
+          final updated =
+              msgs.last.copyWith(content: msgs.last.content + event.text);
+          state = AsyncData([...msgs.sublist(0, msgs.length - 1), updated]);
+        } else if (event is ChatStatusUpdate) {
+          ref.read(streamingStatusProvider(convId).notifier).state =
+              event.status;
+        }
       }
     } catch (_) {
       // SSE failed — fall through to the polling reload below.
@@ -157,6 +179,7 @@ class MessagesNotifier extends AsyncNotifier<List<Message>> {
       }
     } finally {
       ref.read(isStreamingProvider(convId).notifier).state = false;
+      ref.read(streamingStatusProvider(convId).notifier).state = '';
     }
   }
 }