I've thrown Claude and Gemini at the app to try to analyze the code, had them use vmmap and Instruments, asked them run all of the code in a loop to reproduce the leakage — and still it leaks, slowly, tens of megabytes per day.
I'm sure it's something simple starting me in the face. But the fact remains that Swift's sort-of-automatic-but-not-quite memory model still makes it much harder to reason about memory than Rust or even Go.