Restructure modules/shared and update all imports

- Delete 2024-12-rework/ folder
- Rename modules/hosts/common to modules/shared, then split into:
  - modules/shared/home/general
  - modules/shared/home/linux
  - modules/shared/nixos
- Update all import paths throughout the codebase
- Update lib/*.nix to use new paths
- Fix hardcoded /Users/${username} to use config.home.homeDirectory
- Update README and examples/flake-structure.nix

modules/shared/home/linux/default.nix

@@ -0,0 +1,17 @@
+{ pkgs, ... }: {
+  home.packages = with pkgs; [
+    fastfetch
+  ];
+
+  programs = {
+    # Linux-specific aliases
+    zsh.shellAliases = {
+      nixboot = "sudo nixos-rebuild boot --flake ~/repos/dots && echo 'Time to reboot!'";
+      nixdiff = "cd ~/repos/dots && nixos-rebuild build --flake . && nvd diff /run/current-system result";
+      nixup = "sudo nixos-rebuild switch --flake ~/repos/dots";
+      uwgconnect = "nmcli dev wifi connect SecureWest password";
+      uwgforget = "nmcli connection delete SecureWest";
+      ykey = "sudo systemctl restart pcscd && sudo pkill -9 gpg-agent && source ~/.zshrc; ssh-add -L";
+    };
+  };
+}