feat: implement trajectory discovery and resumption logic (Stage 2)

packages/cli/src/ui/commands/chatCommand.ts

@@ -183,9 +183,9 @@ const resumeCheckpointCommand: SlashCommand = {
     const config = context.services.agentContext?.config;
     await logger.initialize();
     const checkpoint = await logger.loadCheckpoint(tag);
-    const conversation = checkpoint.history;
+    const conversation = checkpoint.history ?? [];
 
-    if (conversation.length === 0) {
+    if (conversation.length === 0 && !checkpoint.messages) {
       return {
         type: 'message',
         messageType: 'info',
@@ -233,6 +233,8 @@ const resumeCheckpointCommand: SlashCommand = {
       type: 'load_history',
       history: uiHistory,
       clientHistory: conversation,
+      messages: checkpoint.messages,
+      version: checkpoint.version,
     };
   },
   completion: async (context, partialArg) => {

packages/cli/src/ui/hooks/slashCommandProcessor.ts

@@ -549,7 +549,16 @@ export const useSlashCommandProcessor = (
                     }
                   }
                 case 'load_history': {
-                  config?.getGeminiClient()?.setHistory(result.clientHistory);
+                  const client = config?.getGeminiClient();
+                  if (result.version === '2.0' && client) {
+                    await client.resumeChat(
+                      [...result.clientHistory],
+                      undefined,
+                      result.messages,
+                    );
+                  } else {
+                    client?.setHistory(result.clientHistory);
+                  }
                   fullCommandContext.ui.clear();
                   result.history.forEach((item, index) => {
                     fullCommandContext.ui.addItem(item, index);