[Switch] Expose SoC and PCB temperature to scripts

[ferrolho]

The problem

There is no way to read the console's thermal sensors from a project, so a suspected overheat cannot be diagnosed after the fact. OS has no thermal API, so there is nothing to call from GDScript.

The change

NintendoSwitch.get_soc_temperature()   # Celsius, -1.0 if unavailable
NintendoSwitch.get_pcb_temperature()
NintendoSwitch.get_temperature(NintendoSwitch.TEMPERATURE_SOC)

This follows the pattern already used for the virtual keyboard: methods on the NintendoSwitch singleton, bound through ClassDB. tsInitialize() sits next to psmInitialize() in OS_Switch::initialize(), and tsExit() next to psmExit() in cleanup().

Firmware coverage

tsGetTemperatureMilliC() looks like the obvious choice for precision, but it is documented [1.0.0-13.2.1] and is missing on current firmware, so it is not used here.

Instead this prefers the session API (tsOpenSession and tsSessionGetTemperature, [10.0.0+], returns a float) and falls back to whole-degree tsGetTemperature() on older firmware. Sessions are opened once. If one fails to open, the ones already opened are closed rather than leaked.

Note that TsLocation_Internal is the PCB and TsLocation_External is the SoC, which reads backwards at a glance. The enum here is named TEMPERATURE_PCB and TEMPERATURE_SOC so callers do not have to remember that.

Testing

Tested on a v1 Switch with Atmosphère, docked in an enclosed TV unit, over a 98 minute session sampling at 1 Hz (390 samples):

	start	end	peak
SoC	50.9C	61.2C	61.4C
PCB	47.9C	57.4C	57.4C

Values track load and rise slowly over a long session, which is what an enclosed shelf would suggest. Returns -1.0 cleanly when the sensors are unavailable.