feat: wire discuss button in briefing RSS cards, cap cards at 3

Adds discussArticle() to BriefingApi and wires it through to the
RSS news cards in BriefingScreen so tapping Discuss opens a chat
conversation seeded with the article. Also caps RSS cards per
message at 3 to avoid overly long briefing threads.

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

windows/flutter/generated_plugin_registrant.cc

@@ -9,6 +9,7 @@
 #include <flutter_inappwebview_windows/flutter_inappwebview_windows_plugin_c_api.h>
 #include <flutter_timezone/flutter_timezone_plugin_c_api.h>
 #include <permission_handler_windows/permission_handler_windows_plugin.h>
+#include <record_windows/record_windows_plugin_c_api.h>
 #include <url_launcher_windows/url_launcher_windows.h>
 
 void RegisterPlugins(flutter::PluginRegistry* registry) {
@@ -18,6 +19,8 @@ void RegisterPlugins(flutter::PluginRegistry* registry) {
       registry->GetRegistrarForPlugin("FlutterTimezonePluginCApi"));
   PermissionHandlerWindowsPluginRegisterWithRegistrar(
       registry->GetRegistrarForPlugin("PermissionHandlerWindowsPlugin"));
+  RecordWindowsPluginCApiRegisterWithRegistrar(
+      registry->GetRegistrarForPlugin("RecordWindowsPluginCApi"));
   UrlLauncherWindowsRegisterWithRegistrar(
       registry->GetRegistrarForPlugin("UrlLauncherWindows"));
 }

windows/flutter/generated_plugins.cmake

@@ -6,6 +6,7 @@ list(APPEND FLUTTER_PLUGIN_LIST
   flutter_inappwebview_windows
   flutter_timezone
   permission_handler_windows
+  record_windows
   url_launcher_windows
 )