feat(shell): zsh tooling, tmux plugins, nix-index, nh

zsh: history tuning (100k, dedup, share, timestamps); oh-my-zsh sudo /
colored-man-pages / extract; fzf, zoxide, direnv (+nix-direnv), eza, bat;
ls-family aliases. command-not-found via the prebuilt nix-index DB (+comma).
nh with $NH_FLAKE and a weekly user-GC timer.

tmux: escape-time 10 (was the 500ms default -> laggy vim ESC), focus-events,
base-index 1; plugins sensible / vim-tmux-navigator / yank / catppuccin
(mocha statusline) / resurrect / continuum (restore on); renumber-windows
and set-clipboard.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lyrathorpe/home/shell.nix

@@ -1,6 +1,17 @@
 # Interactive shell: zsh + tmux. Wanted on every host.
-{ lib, ... }:
 {
+  lib,
+  pkgs,
+  inputs,
+  ...
+}:
+{
+  imports = [
+    # Prebuilt nix-index database -> working command-not-found
+    # ("cmd not found -> which nix package provides it"), no manual indexing.
+    inputs.nix-index-database.homeModules.default
+  ];
+
   programs.zsh = {
     enable = true;
     enableCompletion = true;
@@ -21,12 +32,24 @@
         "^[OB"
       ];
     };
-    history.append = true;
+    history = {
+      append = true; # append, don't overwrite, on shell exit
+      size = 100000; # in-memory (HISTSIZE)
+      save = 100000; # on-disk (SAVEHIST)
+      ignoreDups = true; # drop consecutive duplicates
+      ignoreSpace = true; # leading-space commands stay out of history
+      expireDuplicatesFirst = true;
+      share = true; # live-share history across sessions
+      extended = true; # record timestamps
+    };
     oh-my-zsh = {
       enable = true;
       plugins = [
         "git"
         "man"
+        "sudo" # double-Esc prefixes the last command with sudo
+        "colored-man-pages"
+        "extract" # `extract <archive>` for any format
       ];
       theme = "robbyrussell";
     };
@@ -37,9 +60,59 @@
         export PS1="%M $PS1"
       fi
     '';
-    envExtra = ''
-      alias cls=clear
-    '';
+    shellAliases = {
+      # eza's zsh integration also defines these; set explicitly so the
+      # icons/git intent is obvious.
+      ls = "eza --icons --git";
+      ll = "eza --icons --git -l";
+      la = "eza --icons --git -la";
+      lt = "eza --icons --git --tree";
+      cls = "clear";
+    };
+  };
+
+  # Fuzzy finder: Ctrl-R fuzzy history, Ctrl-T files, Alt-C cd.
+  programs.fzf = {
+    enable = true;
+    enableZshIntegration = true;
+  };
+
+  # Frecency directory jumping: `z <fragment>`.
+  programs.zoxide = {
+    enable = true;
+    enableZshIntegration = true;
+  };
+
+  # Per-project environments auto-loaded on cd, with the Nix dev-shell cache.
+  programs.direnv = {
+    enable = true;
+    nix-direnv.enable = true;
+  };
+
+  # Modern ls (drives the ls aliases above).
+  programs.eza = {
+    enable = true;
+    git = true;
+    icons = "auto"; # boolean form is deprecated
+  };
+
+  # Syntax-highlighting pager, used as `bat` (acts like cat when piped).
+  programs.bat.enable = true;
+
+  # command-not-found backed by the prebuilt nix-index DB (module imported
+  # above). `comma` runs an uninstalled program once: `, cowsay hi`.
+  programs.nix-index.enable = true;
+  programs.nix-index-database.comma.enable = true;
+
+  # Nicer nixos-rebuild/home-manager (diffs) + a weekly user-GC timer.
+  programs.nh = {
+    enable = true;
+    flake = "$HOME/code/nixfiles";
+    clean = {
+      enable = true;
+      dates = "weekly";
+      extraArgs = "--keep 5 --keep-since 3d";
+    };
   };
 
   programs.tmux = {
@@ -50,6 +123,33 @@
     keyMode = "vi";
     historyLimit = 500000;
     mouse = true;
+    escapeTime = 10; # was the 500ms default -> laggy ESC in vim
+    focusEvents = true; # let vim see focus changes (autoread)
+    baseIndex = 1; # sets both base-index and pane-base-index
+
+    plugins = with pkgs.tmuxPlugins; [
+      sensible
+      vim-tmux-navigator # Ctrl-h/j/k/l across vim splits and tmux panes
+      yank
+      {
+        # Catppuccin Mocha statusline (v2 API: flavour + window options must be
+        # set before the plugin loads, which home-manager does for plugin
+        # extraConfig; the status modules below go in the main extraConfig,
+        # which HM appends after all plugins).
+        plugin = catppuccin;
+        extraConfig = ''
+          set -g @catppuccin_flavor 'mocha'
+          set -g @catppuccin_window_status_style 'rounded'
+        '';
+      }
+      resurrect # save/restore sessions
+      {
+        plugin = continuum; # auto-save + restore on tmux start (after resurrect)
+        extraConfig = ''
+          set -g @continuum-restore 'on'
+        '';
+      }
+    ];
     # `reverseSplit = true` already binds s -> vertical and v -> horizontal
     # split (the dotfiles' vim-style splits).
     extraConfig = ''
@@ -75,6 +175,18 @@
       set -as terminal-features ",foot*:title"
       set -as terminal-features ",foot*:ccolour"
       set -as terminal-features ",foot*:cstyle"
+
+      # No home-manager options for these.
+      set -g renumber-windows on
+      set -g set-clipboard on
+
+      # Catppuccin v2 statusline. Must run after the plugin has loaded;
+      # home-manager appends this extraConfig after the whole plugin list.
+      set -g status-left-length 100
+      set -g status-right-length 100
+      set -g status-left ""
+      set -g status-right "#{E:@catppuccin_status_application}"
+      set -ag status-right "#{E:@catppuccin_status_session}"
     '';
   };
 }