Major hardware update: toolhead switching, DC/DC protection, and documentation overhaul

Hardware Changes:
- Replaced reverse polarity protection with 2x PFET toolhead switching (PB2/PA5 control)
- Added SS56 Schottky diode reverse polarity protection for DC/DC converter
- Updated current limit resistor to 5.1kΩ (~10.2A)
- Removed fan control circuitry and JST-XH connector
- Removed internal JST-XH USB port with fuse/protection

Documentation Updates:
- Updated both README files to reflect hardware changes
- Removed all fan control references and configurations
- Updated Klipper configuration examples
- Cleaned up pinout and connector assignments
- Updated technical specifications table
- Fixed table of contents and cross-references

EWS.kicad_pro

@@ -48,7 +48,7 @@
         "silk_text_thickness": 0.1,
         "silk_text_upright": false,
         "zones": {
-          "min_clearance": 0.1
+          "min_clearance": 0.25
         }
       },
       "diff_pair_dimensions": [
@@ -184,7 +184,7 @@
         "min_track_width": 0.0,
         "min_via_annular_width": 0.1,
         "min_via_diameter": 0.2,
-        "solder_mask_to_copper_clearance": 0.0,
+        "solder_mask_to_copper_clearance": 0.005,
         "use_height_for_length_calcs": true
       },
       "teardrop_options": [
@@ -573,7 +573,7 @@
       },
       {
         "netclass": "24V",
-        "pattern": "/Connectivity/GATE"
+        "pattern": "/Connectivity/*GATE*"
       },
       {
         "netclass": "24V",