IANA lawyer, but my understanding is that you are correct. The LGPL doesn't force you to release the entire source, unless you are shipping a single static binary. If you dynamically link, you are good to go.
Perfect for me: develop the front end using Qt (on an OSS licence) and Go, which is just a dumb data rendering layer with caching, and keep all the actual business logic server-side. I'll happily open-source a "shell" :)