Add linting, formatting, and CI

- Add deadnix, nixfmt, and statix to flake inputs
- Add formatter output to flake for nix fmt support
- Add deadnix, nixfmt, statix to Home Manager packages
- Format all nix files with nixfmt
- Add GitHub Actions workflow for CI validation
- Support x86_64-darwin in formatter

modules/hosts/nixos/rainbow-planet/hardware-configuration.nix

@@ -1,36 +1,51 @@
 # Do not modify this file!  It was generated by ‘nixos-generate-config’
 # and may be overwritten by future invocations.  Please make changes
 # to /etc/nixos/configuration.nix instead.
-{ config, lib, modulesPath, pkgs, ... }:
+{
+  config,
+  lib,
+  modulesPath,
+  pkgs,
+  ...
+}:
 
 {
-  imports =
-    [ (modulesPath + "/installer/scan/not-detected.nix")
-    ];
+  imports = [
+    (modulesPath + "/installer/scan/not-detected.nix")
+  ];
 
-  boot.initrd.availableKernelModules = [ "xhci_pci" "nvme" "usb_storage" "sd_mod" "rtsx_pci_sdmmc" ];
+  boot.initrd.availableKernelModules = [
+    "xhci_pci"
+    "nvme"
+    "usb_storage"
+    "sd_mod"
+    "rtsx_pci_sdmmc"
+  ];
   # boot.kernelPackages = pkgs.linuxPackages_zen;
   boot.initrd.kernelModules = [ ];
-  boot.kernelModules = [ "kvm-intel" "sg" ];
+  boot.kernelModules = [
+    "kvm-intel"
+    "sg"
+  ];
   boot.kernelParams = [
     "i915.enable_fbc=1"
     "i915.enable_psr=2"
   ];
   boot.extraModulePackages = [ ];
 
-  fileSystems."/" =
-    { device = "/dev/disk/by-uuid/eb9a2c7e-ae61-4d06-9464-49b98d576f7c";
-      fsType = "ext4";
-    };
+  fileSystems."/" = {
+    device = "/dev/disk/by-uuid/eb9a2c7e-ae61-4d06-9464-49b98d576f7c";
+    fsType = "ext4";
+  };
 
-  fileSystems."/boot" =
-    { device = "/dev/disk/by-uuid/924D-E7A4";
-      fsType = "vfat";
-    };
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-uuid/924D-E7A4";
+    fsType = "vfat";
+  };
 
-  swapDevices =
-    [ { device = "/dev/disk/by-uuid/166d24ca-401c-492e-845d-bb1d0d6d7d86"; }
-    ];
+  swapDevices = [
+    { device = "/dev/disk/by-uuid/166d24ca-401c-492e-845d-bb1d0d6d7d86"; }
+  ];
 
   # Enables DHCP on each ethernet and wireless interface. In case of scripted networking
   # (the default) this is the recommended approach. When using systemd-networkd it's