Fix little-rascal touchpad support and update AMD GPU config

- Add ITE8353 touchpad support with I2C HID modules
- Configure libinput for proper touchpad functionality
- Add udev rules for touchpad device permissions
- Simplify AMD GPU config to use open source drivers only
- Remove ROCm and 32-bit support for cleaner configuration
- Add diagnostic script for touchpad troubleshooting

modules/desktop/input.nix

@@ -0,0 +1,54 @@
+# Input Configuration Module
+# Handles touchpad, keyboard, and other input devices
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: {
+  # Enable libinput for touchpad support
+  # This is the recommended touchpad driver for NixOS since 17.09
+  services.libinput = {
+    enable = true;
+
+    # Touchpad-specific settings
+    touchpad = {
+      # Enable tap-to-click (can be disabled if unwanted)
+      tapping = true;
+
+      # Enable two-finger scrolling
+      scrollMethod = "twofinger";
+
+      # Enable natural scrolling (macOS-style, disable if you prefer traditional)
+      naturalScrolling = false;
+
+      # Disable touchpad while typing to prevent accidental input
+      disableWhileTyping = true;
+
+      # Middle button emulation (three-finger tap)
+      middleEmulation = true;
+    };
+
+    # Mouse settings (for external mice)
+    mouse = {
+      # Standard settings for mice
+      naturalScrolling = false;
+      accelProfile = "adaptive";
+    };
+  };
+
+  # Additional input packages that might be useful
+  environment.systemPackages = with pkgs; [
+    # Input device utilities
+    libinput-gestures # For custom touchpad gestures
+    evtest # For testing input devices
+    xinput # X11 input device utility (still useful in Wayland)
+  ];
+
+  # Enable support for additional input methods if needed
+  # (This is separate from touchpad functionality)
+  i18n.inputMethod = {
+    enable = false; # Set to true if you need input methods for other languages
+    # type = "ibus";  # Uncomment and configure if needed
+  };
+}