Were LLMs used to produce some of the writing? Not sure how to describe it, but it has a certain recognizable writing style (e.g. "The Problem"/"The Solution", lots of bulleted lists with bolded first words, etc.) Readers might appreciate if AI use is disclosed.

I've built certified systems (munitions), and the pain of certification is almost always in the process not the coding.

The process is expensive, rigorous and lengthy. It's the process that certifies something good enough to get the stamp for release, not the code design or architecture.

  int64_t age = now - then;  // UNDEFINED BEHAVIOUR if overflow!

  uint64_t age = now - then;  // DEFINED: wraps at 2⁶⁴