fix(ai): join multi-word arguments in cmd_ai_correct

Use g_strjoinv to join all arguments from args[1] onwards into a
single prompt string. Previously only args[1] was used, truncating
multi-word prompts like '/ai correct hello world' to just 'hello'

src/command/cmd_funcs.c

@@ -10855,7 +10855,9 @@ gboolean
 cmd_ai_correct(ProfWin* window, const char* const command, gchar** args)
 {
     // /ai correct <message>
-    if (args[1] == NULL) {
+    // Join all arguments from args[1] onwards to support multi-word prompts
+    auto_gchar gchar* prompt = g_strjoinv(" ", &args[1]);
+    if (prompt == NULL || strlen(prompt) == 0) {
         cons_bad_cmd_usage(command);
         return TRUE;
     }
@@ -10892,11 +10894,11 @@ cmd_ai_correct(ProfWin* window, const char* const command, gchar** args)
     // Replace the last user message
     AIMessage* msg = last_user_msg->data;
     g_free(msg->content);
-    msg->content = g_strdup(args[1]);
+    msg->content = g_strdup(prompt);
 
     // Resend the prompt
     cons_show("Correcting message...");
-    ai_send_prompt(aiwin->session, args[1], aiwin);
+    ai_send_prompt(aiwin->session, prompt, aiwin);
 
     return TRUE;
 }