refactor: extract shell setup

shell/zsh.nix

@@ -0,0 +1,29 @@
+{ theme, ... }:
+let
+  zsh_autosuggest_highlight_style = if theme == "light" then "fg=180" else "fg=10";
+in
+{
+  programs.zsh = {
+    enable = true;
+    enableCompletion = true;
+    history.size = 10000;
+
+    autosuggestion = {
+      enable = true;
+      highlight = zsh_autosuggest_highlight_style;
+    };
+
+    syntaxHighlighting = {
+      enable = true;
+    };
+
+    initExtra = ''
+      function set_win_title(){
+          local TITLE=$(git config --get remote.origin.url || echo "$PWD")
+          echo -ne "\033]0; $(basename "$TITLE") \007"
+      }
+
+      precmd_functions+=(set_win_title)
+    '';
+  };
+}