Simulating limits will be included in the next release.
Hysteresis is something more difficult, so will not handle any time soon.
Asymmetric systems can be handled by gain-scheduling the PID (make a model for each region and schedule the gains), this is approachable in the middle term.
Eg. "Heater output to get to desired temperature", "Motor PWM to get to specified position", etc. Perhaps each with a little diagram/animation showing the input, the output, and some example data.
Could you go into a bit more detail regarding the webassembly implementation in:
pidtuner.github.io/pid/v1.0.6/pid_tuner_wasm.wasm
Is it in C, C++, rust? Could you give a brief description of the internal logic?
The most complex part is the identification algorithm, which uses this algorithm: https://math.stackexchange.com/questions/1428566/fit-sum-of-...
I wonder if it could be portable to a microcontroller Are the blas routines expensive or large matrices?