refactor: fully rebase to nixpkgs-unstable rather than fixed release with backports

hosts/shared/darwin.nix

@@ -77,6 +77,7 @@
       btop
       nerd-fonts.hack
       jump
+      ripgrep
     ];
   };
 

hosts/shared/nixos-pc.nix

@@ -5,9 +5,6 @@
   inputs,
   ...
 }:
-let
-  unstable = inputs.nixpkgs-unstable.legacyPackages.${pkgs.stdenv.hostPlatform.system};
-in
 {
   boot = {
     loader = {
@@ -359,8 +356,8 @@ in
           doCheck = false;
         });
       })
+
       inputs.affinity-nix.overlays.default
-      inputs.nix-cachyos-kernel.overlays.default
     ];
   };
 
@@ -410,13 +407,13 @@ in
       hunspellDicts.en_US
       hyphenDicts.en_US
       affinity-v3
-
-      unstable.libreoffice-qt
-      unstable.qimgv
-      unstable.fastfetch
-      unstable.vorta
-      unstable.distrobox
-      unstable.devenv
+      libreoffice-qt
+      qimgv
+      fastfetch
+      vorta
+      distrobox
+      devenv
+      ripgrep
 
       inputs.appimage-manager.packages.${pkgs.stdenv.hostPlatform.system}.default
       inputs.gloomberb.packages.${pkgs.stdenv.hostPlatform.system}.default
@@ -430,7 +427,7 @@ in
       ))
 
       (callPackage ../../packages/virtiofsd-looking-glass/package.nix { })
-      (callPackage ../../packages/heidisql/package.nix { pkgs = unstable; })
+      (callPackage ../../packages/heidisql/package.nix { })
       (callPackage ../../packages/looking-glass-client/package.nix { })
     ];
 

hosts/shared/nixos-server.nix

@@ -1,13 +1,8 @@
 {
-  config,
   pkgs,
-  lib,
   inputs,
   ...
 }:
-let
-  unstable = inputs.nixpkgs-unstable.legacyPackages.${pkgs.stdenv.hostPlatform.system};
-in
 {
   boot.loader = {
     systemd-boot.enable = true;
@@ -186,8 +181,8 @@ in
       openjdk17
       openjdk25
       tmux
-
-      unstable.fastfetch
+      fastfetch
+      ripgrep
 
       (python3.withPackages (
         python-pkgs: with python-pkgs; [