feat(home): theme CLI tools, add staples, env defaults and mime apps

- Catppuccin Mocha for fzf (colors), bat (catppuccin/bat tmTheme) and
  git delta (syntax-theme + navigate/line-numbers/side-by-side).
- CLI staples on every host: ripgrep, fd, jq, btop, plus gh (SSH) and
  tea (Gitea CLI).
- home.sessionVariables: PAGER, MANPAGER (bat), VISUAL; xdg.enable.
- xdg.mimeApps defaults (web->Firefox, directories->nemo).
- Document the stateVersion pin. README updated.

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

flake.nix

@@ -34,6 +34,18 @@
       url = "github:nix-community/nix-index-database";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    # treefmt-nix: one multi-language formatter driving `nix fmt` and the
+    # formatting flake check (nixfmt + shfmt + prettier).
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    # git-hooks.nix: declarative pre-commit hooks (nixfmt/deadnix/statix),
+    # installed into the repo via the devShell.
+    git-hooks = {
+      url = "github:cachix/git-hooks.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs =
@@ -53,7 +65,7 @@
       let
         # claude-code tracks nixpkgs-unstable regardless of the pinned nixpkgs.
         overlays = [
-          (final: prev: {
+          (_final: prev: {
             claude-code =
               (import nixpkgs-unstable {
                 inherit (prev.stdenv.hostPlatform) system;
@@ -245,7 +257,7 @@
             ];
             homeModules = [
               ./lyrathorpe/home
-              ./system/modules/work/default.nix
+              ./lyrathorpe/home/work.nix
             ];
           };
         };
@@ -268,6 +280,13 @@
         };
       in
       {
+        # flake-parts modules: treefmt-nix wires `nix fmt` + a formatting check;
+        # git-hooks.nix wires the pre-commit check + devShell installation script.
+        imports = [
+          inputs.treefmt-nix.flakeModule
+          inputs.git-hooks.flakeModule
+        ];
+
         systems = [
           "x86_64-linux"
           "aarch64-linux"
@@ -279,26 +298,60 @@
         # nixpkgs instance for that system. Outputs here become per-system
         # attrsets automatically (e.g. devShells.<system>.default).
         perSystem =
-          { pkgs, ... }:
+          { config, pkgs, ... }:
           {
-            # `nix fmt` formatter for the repo.
+            # treefmt drives `nix fmt` and the formatting check below. nixfmt
-            formatter = pkgs.nixfmt;
+            # stays the .nix formatter (the tree is already nixfmt-formatted);
+            # shfmt covers shell and prettier covers markdown/yaml/json.
+            treefmt = {
+              projectRootFile = "flake.nix";
+              programs.nixfmt.enable = true;
+              programs.shfmt.enable = true;
+              programs.prettier.enable = true;
+              # Generated hardware-configuration.nix files are not hand-edited.
+              settings.global.excludes = [ "*/hardware-configuration.nix" ];
+            };
+
+            # Pre-commit hooks: format + lint gate run on commit. The same hooks
+            # are exposed as a flake check (pre-commit.check.enable defaults true).
+            pre-commit.settings.hooks = {
+              nixfmt-rfc-style.enable = true;
+              deadnix = {
+                enable = true;
+                # Unused module args ({config,lib,pkgs,...}) are normal; only flag
+                # genuinely dead bindings.
+                settings.noLambdaPatternNames = true;
+              };
+              statix.enable = true; # reads .statix.toml (repeated_keys/empty_pattern disabled)
+            };
+
+            # treefmt-nix exposes its own `checks.treefmt`; alias it to
+            # `formatting` so the existing CI gate (.#checks.*.formatting) keeps
+            # working without churn.
+            checks.formatting = config.treefmt.build.check inputs.self;
+
+            # deadnix / statix lints as standalone flake checks so `nix flake
+            # check` flags dead code and antipatterns independently of pre-commit.
+            checks.deadnix = pkgs.runCommandLocal "check-deadnix" { nativeBuildInputs = [ pkgs.deadnix ]; } ''
+              deadnix --fail --no-lambda-pattern-names ${./.} && touch $out
+            '';
+            checks.statix = pkgs.runCommandLocal "check-statix" { nativeBuildInputs = [ pkgs.statix ]; } ''
+              statix check ${./.} && touch $out
+            '';
 
             # `nix develop` shell with the tooling needed to hack on this flake.
+            # shellHook installs the git pre-commit hooks into the working tree.
             devShells.default = pkgs.mkShellNoCC {
               packages = with pkgs; [
                 nixfmt
                 nil
                 git
+                deadnix
+                statix
+                treefmt
               ];
+              shellHook = config.pre-commit.installationScript;
             };
-
-            checks.formatting =
-              pkgs.runCommandLocal "check-formatting" { nativeBuildInputs = [ pkgs.nixfmt ]; }
-                ''
-                  # Generated hardware-configuration.nix files are excluded.
-                  nixfmt --check $(find ${./.} -name '*.nix' -not -name 'hardware-configuration.nix') && touch $out
-                '';
           };
 
         # Realise the host tables: each entry becomes a {nixos,darwin}Configuration.

lyrathorpe/home/README.md

@@ -7,7 +7,7 @@ home-manager — edit the listed file and rebuild, never the generated dotfiles.
 Keyboard shortcuts have their own reference: [`KEYBINDINGS.md`](./KEYBINDINGS.md).
 
 | Area                                  | Defined in                                            |
-| --- | --- |
+| ------------------------------------- | ----------------------------------------------------- |
 | zsh, CLI tools, tmux, ssh, auto-tmux  | [`shell.nix`](./shell.nix)                            |
 | git (+ delta, commitizen)             | [`git.nix`](./git.nix)                                |
 | vim                                   | [`editor.nix`](./editor.nix)                          |
@@ -22,7 +22,7 @@ on top (work email, its own ssh config, extra packages).
 ## zsh
 
 | Feature                  | Notes                                                                                                                                      |
-| --- | --- |
+| ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------ |
 | oh-my-zsh                | plugins `git`, `man`, `sudo` (Esc-Esc to prepend sudo), `colored-man-pages`, `extract`; theme `robbyrussell`                               |
 | Autosuggestion           | fish-style history suggestions as you type (→ to accept)                                                                                   |
 | Syntax highlighting      | commands coloured by validity as you type                                                                                                  |
@@ -36,16 +36,26 @@ on top (work email, its own ssh config, extra packages).
 ## CLI tools
 
 | Tool                    | What it gives you                                                                                                                                                                                                                   |
-| --- | --- |
+| ----------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `fzf` | `Ctrl-R` fuzzy history, `Ctrl-T` file picker, `Alt-C` fuzzy cd |
+| `fzf`                   | `Ctrl-R` fuzzy history, `Ctrl-T` file picker, `Alt-C` fuzzy cd (Catppuccin-themed)                                                                                                                                                  |
 | `zoxide`                | `z <fragment>` jumps to frecent directories                                                                                                                                                                                         |
 | `direnv` + `nix-direnv` | per-project environments auto-loaded on `cd` (cached Nix dev shells)                                                                                                                                                                |
 | `eza`                   | modern `ls` (drives the ls aliases)                                                                                                                                                                                                 |
-| `bat` | syntax-highlighting pager; behaves like `cat` when piped |
+| `bat`                   | syntax-highlighting pager (Catppuccin Mocha theme); behaves like `cat` when piped; also the `MANPAGER`                                                                                                                              |
+| `ripgrep` / `fd`        | fast search (`rg`) and find (`fd`); also back `fzf`                                                                                                                                                                                 |
+| `jq` / `btop`           | JSON processor; resource monitor                                                                                                                                                                                                    |
+| `gh` / `tea`            | GitHub and Gitea (`code.emmathe.dev`) CLIs; `gh` uses SSH                                                                                                                                                                           |
 | `nix-index`             | `command-not-found`: an unknown command tells you which Nix package provides it (prebuilt DB, no manual indexing)                                                                                                                   |
 | `comma` (`,`)           | run an uninstalled program once: `, cowsay hi`                                                                                                                                                                                      |
 | `nh`                    | nicer `nixos-rebuild`/`home-manager` with diffs; `$NH_FLAKE` set to the repo. No scheduled GC (it could reap paths a running generation still references) — collect garbage manually with `nh clean all` / `nix-collect-garbage -d` |
 
+**Theming:** `fzf`, `bat` and `git`'s `delta` pager are all Catppuccin Mocha,
+driven from the shared `../catppuccin-mocha.nix` palette / the catppuccin/bat
+theme.
+
+**Env & defaults:** `xdg.enable` on; `PAGER`/`MANPAGER` (bat)/`VISUAL` set in
+`default.nix`; `xdg.mimeApps` maps web→Firefox, directories→nemo (`desktop.nix`).
+
 ## tmux
 
 **Auto-start:** opening any interactive terminal — foot, iTerm2, the WSL shell, the
@@ -55,7 +65,7 @@ fire for SSH sessions, VS Code's integrated terminal, already-inside-tmux, or
 non-interactive shells. Escape hatch: `NO_TMUX=1 <terminal>` opens a bare shell.
 
 | Setting                          | Value                                                                                                                                      |
-| --- | --- |
+| -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
 | Mode keys                        | vi                                                                                                                                         |
 | Mouse                            | on                                                                                                                                         |
 | Scrollback                       | 500000 lines                                                                                                                               |
@@ -77,7 +87,7 @@ glyphs — see Fonts.
 **JetBrainsMono Nerd Font** is installed on every host (in `common-nixos.nix`,
 because tmux runs everywhere; the Mac installs it to `/Library/Fonts` via the
 Darwin config). foot uses it as its main font automatically. iTerm2's font is a
-GUI setting — set it to *JetBrainsMono Nerd Font* (Settings → Profiles → Text →
+GUI setting — set it to _JetBrainsMono Nerd Font_ (Settings → Profiles → Text →
 Font) so the tmux statusline glyphs render instead of `?`.
 
 ## git
@@ -86,14 +96,14 @@ Pager is **delta**. **commitizen** is installed on every host; `cz` defaults to
 Conventional Commits.
 
 | Aliases                  |                                                                   |
-| --- | --- |
+| ------------------------ | ----------------------------------------------------------------- |
 | `st` `co` `sw` `br` `ci` | status / checkout / switch / branch / commit                      |
 | `last` `unstage`         | last commit / unstage                                             |
 | `lg`                     | graph log, all branches                                           |
 | `cz` `cc`                | `git cz <sub>` (e.g. `git cz c`) and `git cc` → commitizen prompt |
 
 | Behaviour      |                                                                                                                                                                          |
-| --- | --- |
+| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
 | Pulls          | rebase, with autostash + autosquash                                                                                                                                      |
 | Fetch          | prune deleted remote branches                                                                                                                                            |
 | Conflicts      | `zdiff3` (shows the common ancestor)                                                                                                                                     |
@@ -107,7 +117,7 @@ Conventional Commits.
 ## ssh
 
 | Feature      | Notes                                                                                                                                                |
-| --- | --- |
+| ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------- |
 | ssh-agent    | runs on Linux (launchd on macOS); keys added on **first use** so the passphrase is typed once per login session — this also feeds git commit signing |
 | macOS        | `UseKeychain` caches the passphrase in the login keychain (guarded by `IgnoreUnknown`, so a non-Apple `ssh` skips it instead of erroring)            |
 | Gitea remote | `code.emmathe.dev` → `HostName 10.187.1.76` (DNS-override), `Port 30009`, user `git`, dedicated key, `identitiesOnly`                                |
@@ -127,7 +137,7 @@ forced off there) but still runs the agent.
 ## Per-host differences
 
 |                             | Personal Linux (sway) | macOS             | Work WSL (EDaaS)            |
-| --- | --- | --- | --- |
+| --------------------------- | --------------------- | ----------------- | --------------------------- |
 | Auto-tmux                   | yes (foot/TTY)        | yes (iTerm2)      | yes (WSL shell)             |
 | git email                   | `iam@emmathe.dev`     | `iam@emmathe.dev` | `…@citrix.com` (work)       |
 | ssh config managed          | yes                   | yes               | no (keeps corporate config) |

lyrathorpe/home/default.nix

@@ -9,5 +9,26 @@
     ./editor.nix
   ];
 
+  # Manage the XDG base-directory layout and ~/.config files. Tools above
+  # (bat themes, gh config, ...) write under xdg.configHome; enabling this
+  # makes the paths explicit and consistent across hosts. No regression: the
+  # defaults match the conventional ~/.config, ~/.cache, ~/.local/share.
+  xdg.enable = true;
+
+  # Editor itself comes from vim.defaultEditor (sets $EDITOR). Round out the
+  # rest of the standard env. desktop.nix adds its own Wayland session vars;
+  # home-manager merges the two attrsets, so these do not clash.
+  home.sessionVariables = {
+    VISUAL = "vim";
+    PAGER = "less -FRX"; # -F quit-if-one-screen, -R raw colour, -X no clear
+    # Render man pages through bat (themed): col strips backspace overstrike,
+    # bat -l man -p highlights without its own pager decorations.
+    MANPAGER = "sh -c 'col -bx | bat -l man -p'";
+  };
+
+  # Pinned to the release first installed on these hosts, NOT the current
+  # nixpkgs (26.05). stateVersion freezes stateful defaults (file locations,
+  # service data formats) to that release; bumping it silently migrates that
+  # state and can break it. Leave it -- it is intentional, not stale.
   home.stateVersion = "25.05";
 }

lyrathorpe/home/desktop.nix

@@ -27,6 +27,30 @@
     XDG_CURRENT_DESKTOP = "sway";
   };
 
+  # Default apps for the desktop (writes ~/.config/mimeapps.list). Firefox owns
+  # the web; nemo owns directories/file URIs; images, PDFs and plain text open
+  # in Firefox too -- no dedicated GUI viewer/editor is installed and vim is
+  # terminal-only (no usable GUI .desktop for double-click handoff). Kept
+  # minimal -- only the handlers actually present on these hosts.
+  xdg.mimeApps = {
+    enable = true;
+    defaultApplications = {
+      "text/html" = "firefox.desktop";
+      "x-scheme-handler/http" = "firefox.desktop";
+      "x-scheme-handler/https" = "firefox.desktop";
+      "x-scheme-handler/about" = "firefox.desktop";
+      "x-scheme-handler/unknown" = "firefox.desktop";
+      "inode/directory" = "nemo.desktop";
+      "image/png" = "firefox.desktop";
+      "image/jpeg" = "firefox.desktop";
+      "image/gif" = "firefox.desktop";
+      "image/webp" = "firefox.desktop";
+      "image/svg+xml" = "firefox.desktop";
+      "application/pdf" = "firefox.desktop";
+      "text/plain" = "firefox.desktop";
+    };
+  };
+
   # Theme GTK apps (nemo, etc.) to match the Catppuccin Mocha desktop. Under
   # Sway there is no XSettings daemon, so GTK reads these from the generated
   # ~/.config/gtk-{3,4}.0/settings.ini directly. The Mocha theme is dark by

lyrathorpe/home/git.nix

@@ -37,6 +37,17 @@
         colorMoved = "default";
       };
       rerere.enabled = true; # remember + replay conflict resolutions
+
+      # delta pager config (programs.delta is enabled below, with git
+      # integration; these keys land under [delta] in the git config).
+      # syntax-theme reuses the Catppuccin Mocha tmTheme vendored for bat in
+      # shell.nix -- delta reads bat's theme directory.
+      delta = {
+        syntax-theme = "Catppuccin Mocha";
+        navigate = true; # n/N to jump between diff hunks
+        line-numbers = true;
+        side-by-side = true;
+      };
       commit.verbose = true; # full diff in the commit-message editor
       branch.sort = "-committerdate"; # most-recent branches first
       column.ui = "auto";

lyrathorpe/home/shell.nix

@@ -5,6 +5,10 @@
   inputs,
   ...
 }:
+let
+  # Shared Catppuccin Mocha palette: raw 6-hex strings, no leading "#".
+  ctp = import ../catppuccin-mocha.nix;
+in
 {
   imports = [
     # Prebuilt nix-index database -> working command-not-found
@@ -12,6 +16,16 @@
     inputs.nix-index-database.homeModules.default
   ];
 
+  # CLI staples wanted on every host (search, parse, monitor). ripgrep/fd also
+  # back fzf and editor integrations; tea is the Gitea CLI for code.emmathe.dev.
+  home.packages = [
+    pkgs.ripgrep
+    pkgs.fd
+    pkgs.jq
+    pkgs.btop
+    pkgs.tea
+  ];
+
   programs.zsh = {
     enable = true;
     enableCompletion = true;
@@ -99,6 +113,23 @@
   programs.fzf = {
     enable = true;
     enableZshIntegration = true;
+    # Catppuccin Mocha colours (rendered into FZF_DEFAULT_OPTS --color). Each
+    # value needs a leading "#"; the palette stores raw hex.
+    colors = {
+      "bg" = "#${ctp.base}";
+      "bg+" = "#${ctp.surface1}"; # current line / selected row
+      "fg" = "#${ctp.text}";
+      "fg+" = "#${ctp.text}";
+      "hl" = "#${ctp.blue}"; # match highlights
+      "hl+" = "#${ctp.blue}";
+      "header" = "#${ctp.red}";
+      "info" = "#${ctp.mauve}";
+      "marker" = "#${ctp.green}";
+      "pointer" = "#${ctp.pink}";
+      "prompt" = "#${ctp.mauve}";
+      "spinner" = "#${ctp.pink}";
+      "border" = "#${ctp.surface1}";
+    };
   };
 
   # Frecency directory jumping: `z <fragment>`.
@@ -120,8 +151,22 @@
     icons = "auto"; # boolean form is deprecated
   };
 
-  # Syntax-highlighting pager, used as `bat` (acts like cat when piped).
+  # Syntax-highlighting pager, used as `bat` (acts like cat when piped). bat
-  programs.bat.enable = true;
+  # ships no Catppuccin theme, so vendor the upstream tmTheme from catppuccin/bat
+  # (delta in git.nix reuses it as its syntax-theme).
+  programs.bat = {
+    enable = true;
+    config.theme = "Catppuccin Mocha";
+    themes."Catppuccin Mocha" = {
+      src = pkgs.fetchFromGitHub {
+        owner = "catppuccin";
+        repo = "bat";
+        rev = "6810349b28055dce54076712fc05fc68da4b8ec0";
+        sha256 = "1y5sfi7jfr97z1g6vm2mzbsw59j1jizwlmbadvmx842m0i5ak5ll";
+      };
+      file = "themes/Catppuccin Mocha.tmTheme";
+    };
+  };
 
   # command-not-found backed by the prebuilt nix-index DB (module imported
   # above). `comma` runs an uninstalled program once: `, cowsay hi`.
@@ -138,6 +183,13 @@
     flake = "$HOME/code/nixfiles";
   };
 
+  # GitHub CLI. Prefer SSH for any git operations it drives, matching the
+  # ssh-based remotes used elsewhere.
+  programs.gh = {
+    enable = true;
+    settings.git_protocol = "ssh";
+  };
+
   programs.tmux = {
     enable = true;
     reverseSplit = true;

statix.toml

@@ -0,0 +1,8 @@
+# statix lint config. Two default lints are disabled because they flag this
+# repo's intentional house style, not bugs:
+#   repeated_keys  - we use `foo.a = ...; foo.b = ...;` (dotted) over nesting.
+#   empty_pattern  - module files use `{ ... }:` / `{ }:` deliberately.
+disabled = [
+  "repeated_keys",
+  "empty_pattern",
+]