refactor: Add more checks to pre-commit

Updated existing pre-commit hooks and added some new hooks:

- Remove trailing whitespace
- Ensure every non-empty file ends with a new line
- Check YAML file validity
- Prevent adding large files
- Ensure any scripts with shebangs are executable

Added a GitHub action to run pre-commit on every commit. Removed any
existing actions which duplicate pre-commit.

Ran pre-commit on the codebase.

app/boards/shields/redox/redox.dtsi

@@ -3,7 +3,7 @@
  *
  * SPDX-License-Identifier: MIT
  */
- 
+
 #include <dt-bindings/zmk/matrix_transform.h>
 
 / {
@@ -42,7 +42,7 @@ RC(4,0) RC(4,1) RC(4,2) RC(4,3)      RC(4,4)    RC(4,5) RC(4,6) RC(4,7) RC(4,8)
 			, <&pro_micro 8 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
 			, <&pro_micro 9 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>
 			;
-		
+
 	};
 
 };

app/boards/shields/redox/redox.keymap

@@ -30,7 +30,7 @@
             >;
 
         };
-        
+
         lower_layer {
 // --------------------------------------------------------------------------------------------------------------------------
 // | ESC   |  1  |  2  |   3   |   4   |  5  |                   ---              |  6  |  7  |   8  |  9   |  0  |  DEL  |
@@ -62,7 +62,7 @@
    &trans  &trans    &trans   &mo 3         &trans        &mo 3  &trans &trans &trans        &trans       &trans    &trans   &trans    &trans
             >;
         };
-        
+
         adjust_layer {
 // -----------------------------------------------------------------------------------------
 // |  F1   |  F2   |    F3    |    F4     |     F5     | F6 |                   ---                | F7  | F8  |  F9  |  F10 | F11 | F12        |