Skip session resume prompt when --new-session flag is passed

When users explicitly pass --new-session, they want a fresh session.
Previously g3 would still prompt to resume an existing session.
Now the resume check is skipped entirely when the flag is set.

crates/g3-cli/src/accumulative.rs

@@ -299,6 +299,7 @@ async fn handle_command(
                 cli.show_code,
                 chat_combined_content,
                 workspace_dir,
+                cli.new_session,
             )
             .await?;