Feature request: change MOSFET and Op-amp coloration when at bounds (e.g. saturated output, linear operation, saturated operation)

[kubark42]

One of the awesome things about Falstad/Circuit.js is how the colors help us understand the circuit dynamics. One place where more color to add to understanding is for the MOSFET and the op-amp icons. If those were to change color when the part reaches its limits, that would be a very nice feature.

Here are my proposed colors, but of course any will do:

• MOSFET: Orange when in linear region, green when in saturation region.
• Op-amp: Red when at its lower limit, Green when at its upper limit.

[esaruoho]

I have created a PR that addresses this: pfalstad#290

The implementation adds operating region coloring for MOSFETs and op-amps, toggled via Other Options > Show Operating Region (off by default, persisted in localStorage).

MOSFETs show a colored channel indicator:

• Gray -- cutoff (Vgs < Vth, no channel)
• Blue -- linear/triode region (Vgs > Vth, Vds < Vgs-Vth)
• Green -- saturation (Vgs > Vth, Vds > Vgs-Vth)

Op-amps (both ideal and real LM741/LM324) show a filled triangle when the output is clipping:

• Red fill -- positive saturation (output at V+ rail)
• Blue fill -- negative saturation (output at V- rail)

JFETs also inherit the MOSFET coloring since they extend the same class.