feat: add keybinds to change focused message generation

app/pages/agent/[id]/topic/[topicId].vue

@@ -315,6 +315,30 @@ addShortcut(['alt', ']'], async (event) => {
     }
 })
 
+addShortcut(['ctrl', 'alt', 'arrowleft'], async (event) => {
+    const lastMessage = topic.value?.messages?.at(-1);
+    if (lastMessage && lastMessage.children.length > 0) {
+        event.preventDefault();
+        event.stopPropagation();
+
+        await triplit.update('messages', lastMessage.id, {
+            focusedIndex: Math.max(0, lastMessage.focusedIndex! - 1)
+        });
+    }
+})
+
+addShortcut(['ctrl', 'alt', 'arrowright'], async (event) => {
+    const lastMessage = topic.value?.messages?.at(-1);
+    if (lastMessage && lastMessage.children.length > 0) {
+        event.preventDefault();
+        event.stopPropagation();
+
+        await triplit.update('messages', lastMessage.id, {
+            focusedIndex: Math.min(lastMessage.children.length, lastMessage.focusedIndex! + 1)
+        });
+    }
+})
+
 onMounted(() => {
     scrollToBottom('instant');
 });