Add separate longclick retrigger delay

[eternicode]

Objective

I was trying to implement a standard interaction pattern with long press:

• User presses button
• Press action is executed immediately
• User continues pressing through long press delay (eg, 500ms)
• Long press action is executed
• Much shorter delay (eg, 100ms) is applied while button remains pressed
• Long press action is repeated at shorter interval while button is held

Classic example would be long-pressing to quickly navigate a long list of items.

I had attempted this with (simplified and slightly pseudocode):

btn.setPressedHandler(pressAction);
btn.setLongClickDetectedHandler(
    [this](Button2 &btn) {
        btn.setLongClickTime(100);
        pressAction(btn);
    }
);
btn.setLongClickHandler([this](Button2 &btn) {
    btn.setLongClickTime(500);
});
btn.setLongClickDetectedRetriggerable(true);
btn.setLongClickTime(500);

but this approach consistently caused the first 3-5 long click actions to execute with ~30ms delay. The exact timing is probably dependent on other factors, but the threshold was adjusted downward when setLongClickTime(100) was called, so these 3-5 initial repeats were effectively immediately executed while the timer caught up to the adjusted longclick_counter multiplier math.

The MR produces cleaner behavior with cleaner code:

btn.setPressedHandler(pressAction);
btn.setLongClickDetectedHandler(pressAction);
btn.setLongClickTime(500);
btn.setLongClickDetectedRetriggerable(true, 100);

Considerations

I tried to come up with a clean way to avoid the has_longclick_retrigger_ms variable. Cleanest way would be to have an invalid value for longclick_retrigger_ms, ie -1, but uint to accommodate milliseconds precludes that option. Could default it to longclick_time_ms's value at init and sync the two when they have the same value, but that felt like too much magic. Explicit flagging felt best.

[nielsnl68]

Hi, i like your idea, not sure if the "has_longclick_retrigger_ms" is really needed you could just check if "longclick_retrigger_ms" has a value.

[LennartHennigs]

Thanks for this PR! The bundled API approach here (setLongClickDetectedRetriggerable(bool, unsigned int)) inspired the solution that was ultimately implemented.

I've opened #91 as a hybrid — it takes your API style from this PR and combines it with the cleaner sentinel-based implementation from #90 (no extra bool flag, unsigned long types throughout). Would love your review if you have a moment!