feat: weather card and RSS reactions in briefing screen

- Parse metadata field on Message model (weather, rss_item_ids)
- Add WeatherCard widget: location, current temp, condition, today hi/lo,
  delta from yesterday, scrollable 3-day forecast strip
- BriefingScreen shows WeatherCard above the first assistant message that
  carries weather metadata (mirrors web BriefingView.vue behaviour)
- RSS reaction buttons (👍/👎) shown below assistant messages with
  rss_item_ids; optimistic toggle with rollback on failure
- Add postRssReaction / deleteRssReaction to BriefingApi

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

lib/screens/briefing/briefing_screen.dart

@@ -2,8 +2,11 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../../core/exceptions.dart';
+import '../../data/models/message.dart';
 import '../../providers/briefing_provider.dart';
+import '../../providers/api_client_provider.dart';
 import '../../widgets/chat_message_bubble.dart';
+import '../../widgets/weather_card.dart';
 import 'briefing_history_screen.dart';
 
 class BriefingScreen extends ConsumerStatefulWidget {
@@ -17,6 +20,8 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen> {
   final _controller = TextEditingController();
   final _scrollController = ScrollController();
   bool _refreshing = false;
+  // rss_item_id -> 'up' | 'down' | null
+  final Map<int, String?> _reactions = {};
 
   @override
   void dispose() {
@@ -57,6 +62,22 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen> {
     }
   }
 
+  Future<void> _handleReaction(int itemId, String reaction) async {
+    final current = _reactions[itemId];
+    final next = current == reaction ? null : reaction;
+    setState(() => _reactions[itemId] = next);
+    final api = ref.read(briefingApiProvider);
+    try {
+      if (next == null) {
+        await api.deleteRssReaction(itemId);
+      } else {
+        await api.postRssReaction(itemId, reaction);
+      }
+    } catch (_) {
+      setState(() => _reactions[itemId] = current);
+    }
+  }
+
   Future<void> _refresh() async {
     setState(() => _refreshing = true);
     try {
@@ -178,8 +199,14 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen> {
                             horizontal: 8, vertical: 8),
                         sliver: SliverList.builder(
                           itemCount: conv.messages.length,
-                          itemBuilder: (_, i) =>
-                              ChatMessageBubble(message: conv.messages[i]),
+                          itemBuilder: (_, i) {
+                            final msg = conv.messages[i];
+                            return _BriefingMessageItem(
+                              message: msg,
+                              reactions: _reactions,
+                              onReaction: _handleReaction,
+                            );
+                          },
                         ),
                       ),
                   ],
@@ -246,6 +273,118 @@ class _BriefingScreenState extends ConsumerState<BriefingScreen> {
   }
 }
 
+/// Renders a single briefing message with optional WeatherCard above it
+/// and RSS reaction buttons below it (for assistant messages with metadata).
+class _BriefingMessageItem extends StatelessWidget {
+  final Message message;
+  final Map<int, String?> reactions;
+  final void Function(int itemId, String reaction) onReaction;
+
+  const _BriefingMessageItem({
+    required this.message,
+    required this.reactions,
+    required this.onReaction,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final meta = message.metadata;
+    final isAssistant = message.role == MessageRole.assistant;
+
+    // Weather: show card above when metadata.weather key is present (even if null value)
+    final bool hasWeatherKey = isAssistant && meta != null && meta.containsKey('weather');
+    final weatherData = hasWeatherKey ? meta['weather'] as Map<String, dynamic>? : null;
+
+    // RSS reactions
+    final rssItemIds = isAssistant && meta != null
+        ? (meta['rss_item_ids'] as List<dynamic>?)?.cast<int>() ?? []
+        : <int>[];
+
+    final scheme = Theme.of(context).colorScheme;
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        if (hasWeatherKey) WeatherCard(weather: weatherData),
+        ChatMessageBubble(message: message),
+        if (rssItemIds.isNotEmpty)
+          Padding(
+            padding: const EdgeInsets.only(left: 8, bottom: 4),
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: rssItemIds.asMap().entries.map((entry) {
+                final index = entry.key;
+                final itemId = entry.value;
+                final current = reactions[itemId];
+                return Padding(
+                  padding: const EdgeInsets.only(top: 4),
+                  child: Row(
+                    mainAxisSize: MainAxisSize.min,
+                    children: [
+                      Text(
+                        'Story ${index + 1}',
+                        style: TextStyle(
+                          fontSize: 12,
+                          color: scheme.onSurfaceVariant,
+                        ),
+                      ),
+                      const SizedBox(width: 8),
+                      _ReactionButton(
+                        emoji: '👍',
+                        active: current == 'up',
+                        onTap: () => onReaction(itemId, 'up'),
+                      ),
+                      const SizedBox(width: 4),
+                      _ReactionButton(
+                        emoji: '👎',
+                        active: current == 'down',
+                        onTap: () => onReaction(itemId, 'down'),
+                      ),
+                    ],
+                  ),
+                );
+              }).toList(),
+            ),
+          ),
+      ],
+    );
+  }
+}
+
+class _ReactionButton extends StatelessWidget {
+  final String emoji;
+  final bool active;
+  final VoidCallback onTap;
+
+  const _ReactionButton({
+    required this.emoji,
+    required this.active,
+    required this.onTap,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final scheme = Theme.of(context).colorScheme;
+    return GestureDetector(
+      onTap: onTap,
+      child: AnimatedContainer(
+        duration: const Duration(milliseconds: 150),
+        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
+        decoration: BoxDecoration(
+          color: active
+              ? scheme.primary.withValues(alpha: 0.12)
+              : Colors.transparent,
+          border: Border.all(
+            color: active ? scheme.primary : scheme.outlineVariant,
+          ),
+          borderRadius: BorderRadius.circular(6),
+        ),
+        child: Text(emoji, style: const TextStyle(fontSize: 14)),
+      ),
+    );
+  }
+}
+
 class _GradientSendButton extends StatelessWidget {
   final VoidCallback? onPressed;
   final bool isStreaming;