fix a lot of low level cppcheck warnings (#9623)

* simplify the observer pattern, since all the called functions are const getters.
* use arduino macro over std: for numerical values and refactor local variables in drawScrollbar()
* oh, so Cppcheck actually complained about const pointers not being const.
* slowly getting out of ifdef hell
* fix inkHUD warnings as well
* last 2 check warnings
* git checks should fail on low defects from now on

src/platform/portduino/USBHal.h

@@ -29,7 +29,7 @@ class Ch341Hal : public RadioLibHal
 {
   public:
     // default constructor - initializes the base HAL and any needed private members
-    explicit Ch341Hal(uint8_t spiChannel, std::string serial = "", uint32_t vid = 0x1A86, uint32_t pid = 0x5512,
+    explicit Ch341Hal(uint8_t spiChannel, const std::string &serial = "", uint32_t vid = 0x1A86, uint32_t pid = 0x5512,
                       uint32_t spiSpeed = 2000000, uint8_t spiDevice = 0, uint8_t gpioDevice = 0)
         : RadioLibHal(PI_INPUT, PI_OUTPUT, PI_LOW, PI_HIGH, PI_RISING, PI_FALLING)
     {