feat(home): add git-filter-repo

Idle cache 30 min -> 1 h, absolute cap 2 h -> 8 h. Both `lib.mkDefault` so an
inventory can set `services.gpg-agent.defaultCacheTtl` without `mkForce`.

CLAUDE.md

@@ -48,7 +48,8 @@ declaratively in `modules/home.nix` (`wayland.windowManager.hyprland`, `programs
 `programs.foot`). Font is JetBrainsMono Nerd Font; Waybar/foot use Nerd Font glyphs
 (nf-md set) for icons, so new glyphs should come from that set for visual consistency.
 
-Hyprland uses the **master** layout and a **German** keyboard (`kb_layout = "de"`).
+Hyprland uses the **master** layout; `kb_layout` ships neutral (`mkDefault "us"`),
+overridden per-inventory like `console.keyMap`.
 Look deliberately minimal: animations, blur, rounding, and shadows are all turned
 **off** on purpose — don't reintroduce them when adding desktop tweaks.
 

README.md

@@ -33,7 +33,7 @@ keeps it.
 
 ```
 your-inventory/
-├── flake.nix                        # inputs (pub + follows) + nixosConfigurations.<host>
+├── flake.nix                        # inputs (baseline + your nixpkgs) + nixosConfigurations.<host>
 ├── flake.lock
 ├── system/                          # system-level modules
 │   ├── regional.nix                 # time zone / keymap / locale (see Overriding)
@@ -55,17 +55,22 @@ The `flake.nix` that wires it together:
 ```nix
 {
   inputs = {
-    pub.url = "github:<owner>/<repo>";
+    # You own nixpkgs, so your update cadence is yours — the baseline modules
-    # Reuse the public flake's pins so versions never drift between the two.
+    # build against the versions you pin here.
-    nixpkgs.follows = "pub/nixpkgs";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    home-manager.follows = "pub/home-manager";
+    home-manager.url = "github:nix-community/home-manager";
+    home-manager.inputs.nixpkgs.follows = "nixpkgs";
+
+    baseline.url = "github:<owner>/<repo>";
+    baseline.inputs.nixpkgs.follows = "nixpkgs";        # baseline builds against YOUR nixpkgs
+    baseline.inputs.home-manager.follows = "home-manager";
   };
 
-  outputs = inputs@{ self, nixpkgs, pub, home-manager, ... }: {
+  outputs = inputs@{ self, nixpkgs, baseline, home-manager, ... }: {
     nixosConfigurations.myhost = nixpkgs.lib.nixosSystem {
       system = "x86_64-linux";
       modules = [
-        pub.nixosModules.default          # generic system baseline
+        baseline.nixosModules.default     # generic system baseline
         ./system/regional.nix             # your regional values (see below)
         ./hosts/myhost                    # hardware + hostname
         home-manager.nixosModules.home-manager
@@ -75,7 +80,7 @@ The `flake.nix` that wires it together:
           # Inject your own inputs into your home modules; the public ones ignore them.
           home-manager.extraSpecialArgs = { inherit inputs; };
           home-manager.users.me.imports = [
-            pub.homeModules.default         # generic home baseline
+            baseline.homeModules.default    # generic home baseline
             ./home/identity.nix             # your git identity, name/email, …
             ./home/ssh.nix                  # your SSH hosts (topology stays private)
             # … more personal home modules
@@ -87,9 +92,38 @@ The `flake.nix` that wires it together:
 }
 ```
 
+This repo ships *modules*, not pinned packages: they build against the `nixpkgs` **you**
+declare above, so you decide when packages move. *Quickstart alternative:* drop your own
+`nixpkgs` and write `nixpkgs.follows = "baseline/nixpkgs"` to pin to this repo's tested
+versions instead — one less thing to think about, but then your update cadence is whatever
+this repo pins, not the reverse.
+
 Your machine list, hostnames, and any private specifics stay in *your* flake — you pull
 only the generic modules from here.
 
+## Updating (day-to-day)
+
+**Every** package version comes from the `nixpkgs` **you** declare — including the packages
+this repo's own modules install, since they build against your `nixpkgs` via `follows`, not
+against anything this repo pins. So the whole upgrade happens in your flake; you never touch
+this repo to move packages, even the ones it declares:
+
+```sh
+nix flake update                                 # bump every input to newest
+sudo nixos-rebuild switch --flake .#myhost       # build + activate
+```
+
+`nix flake update` advances `nixpkgs` to the newest commit on the branch you pinned (e.g.
+`nixos-unstable` or `nixos-25.11`) — that is what upgrades your packages. `home-manager` and
+`baseline` **follow** your `nixpkgs`, so they move in lockstep with no version skew. To move
+one input at a time, name it: `nix flake update nixpkgs` bumps only packages;
+`nix flake update baseline` pulls the latest **modules** from this repo (new features/fixes)
+without changing any package version. These are independent knobs — routine upgrades need
+only the `nixpkgs` bump.
+
+A **release jump** (e.g. `nixos-25.11` → `nixos-26.05`) is not a plain update: edit the
+branch in the `nixpkgs` and `home-manager` URLs in your `flake.nix`, then update and rebuild.
+
 ## Overriding the baseline
 
 The public modules are a baseline you extend without forking. Three ways to shape them
@@ -111,6 +145,10 @@ from your private flake, in rough order of how often you reach for them:
    local.texlive.package = pkgs.texlive.withPackages (ps: [ ps.scheme-full ]);
    ```
 
+   A few `local.*` options exist precisely because a module pins a package to a nixpkgs
+   *other* than the one you declare (a deliberate freeze that would otherwise reach you
+   regardless of your own pin); the option is how you pull it back onto your nixpkgs.
+
 3. **Extra modules.** Anything with no public counterpart is just another module in the
    import lists above — personal apps, SSH/Syncthing topology, secrets wiring.
 

flake.lock

@@ -28,11 +28,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1782704057,
+        "lastModified": 1785119570,
-        "narHash": "sha256-G1I1gd32F7mp9LAe1DaZ4ZL7NX5gyiKwdCMwro1Vrck=",
+        "narHash": "sha256-Rgs2xKnGLFWQscxUaXX07oyZeuMDOHEbqDOsgliLFGM=",
         "owner": "nix-community",
         "repo": "home-manager",
-        "rev": "868d0a692de703c2de98fab61968e4e310b7c28e",
+        "rev": "d4fd24667c8cbef124bb70a20380cab75ec8474d",
         "type": "github"
       },
       "original": {
@@ -44,11 +44,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1782691344,
+        "lastModified": 1785858998,
-        "narHash": "sha256-i5nw9BYYsMDAaOC4J+JmTof6b2GhlyH076awYRNrTV8=",
+        "narHash": "sha256-fKCq5jphd6l/Ms6gc3dptkw/TcKLYub9lQE5g6rbbkc=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "1f01958ffb5b3545c96d9ef2f4e24c5e5e1eb846",
+        "rev": "04607e1165ac22c5fde6dcc54c9e0b3c0487c555",
         "type": "github"
       },
       "original": {
@@ -96,11 +96,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1782875958,
+        "lastModified": 1785993740,
-        "narHash": "sha256-5eqDcnBjb1424HRQdnhuhNOBZguq1Z2tqSa2OMF/m2c=",
+        "narHash": "sha256-naSJ+p7zkIT2hHNSJkhxiPZlmVRgE3UdODinMM7rpD8=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "13139aefa973f3d96c60c0fbab801de058ae25ca",
+        "rev": "3d1b34a12a26be073f7ae67165a6b61229ca6025",
         "type": "github"
       },
       "original": {

modules/dictionaries.nix

@@ -0,0 +1,53 @@
+# Hunspell dictionaries, joined into one directory so anything needing a
+# dictionary *path* can be pointed at a single store path.
+#
+# Two consumers, two mechanisms:
+#   - LibreOffice needs nothing beyond the package being installed: its wrapper
+#     scans `share/hunspell` in every NIX_PROFILES entry.
+#   - Gecko apps (LibreWolf, Thunderbird) need `spellchecker.dictionary_path`
+#     set explicitly — there is no /usr/share/hunspell on NixOS and wrapFirefox
+#     wires up nothing itself. Point that pref at `local.dictionaries.path`.
+#
+# Chromium-based browsers are NOT served by this: they ignore hunspell and
+# fetch their own dictionaries, selected by enterprise policy.
+#
+# Which languages is a personal choice, so the default is empty; a consumer sets
+# `local.dictionaries.packages = [ pkgs.hunspellDicts.de_DE ];`. en-US ships
+# inside Firefox/Thunderbird already and does not need listing for those.
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.local.dictionaries;
+
+  joined = pkgs.symlinkJoin {
+    name = "hunspell-dicts";
+    paths = cfg.packages;
+  };
+in
+{
+  options.local.dictionaries = {
+    packages = lib.mkOption {
+      type = lib.types.listOf lib.types.package;
+      default = [ ];
+      example = lib.literalExpression "[ pkgs.hunspellDicts.de_DE ]";
+      description = ''
+        Hunspell dictionary packages to install and expose via
+        `local.dictionaries.path`.
+      '';
+    };
+
+    path = lib.mkOption {
+      type = lib.types.str;
+      readOnly = true;
+      description = ''
+        Directory holding every `packages` dictionary. Feed this to
+        `spellchecker.dictionary_path` in Gecko apps.
+      '';
+    };
+  };
+
+  config = {
+    local.dictionaries.path = "${joined}/share/hunspell";
+    home.packages = lib.optional (cfg.packages != [ ]) joined;
+  };
+}

modules/gpg.nix

@@ -2,7 +2,7 @@
 # signing identity — those are personal (→ inventory). Enabling this alone is
 # harmless: a user with no key just has an idle agent.
 
-{ config, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 {
   programs.gpg = {
@@ -26,7 +26,12 @@
     # sk-based ssh keys use the normal ssh-agent; don't let gpg-agent hijack
     # SSH_AUTH_SOCK.
     enableSshSupport = false;
-    defaultCacheTtl = 1800;   # 30 min
+    # Idle timer, reset on every use. The hard cap runs from the unlock and
-    maxCacheTtl = 7200;       # 2 h
+    # never resets, so a machine in continuous use still re-asks once a workday —
+    # otherwise an unattended unlocked session signs forever.
+    # mkDefault so an inventory can dial these per machine with a plain
+    # `services.gpg-agent.defaultCacheTtl = …;` and no mkForce.
+    defaultCacheTtl = lib.mkDefault 3600;   # 1 h idle
+    maxCacheTtl = lib.mkDefault 28800;      # 8 h absolute
   };
 }

modules/home.nix

@@ -115,14 +115,17 @@ let
       | "keyword monitor \($l.name),preferred,0x0,\($l.scale)"
       + " ; keyword monitor \($r.name),preferred,\($off)x0,\($r.scale)"')
     "$hc" --batch "$cmd"
-    # re-anchor the layer-shell clients onto the new geometry (see comment above)
+    # re-anchor the layer-shell clients onto the new geometry (see comment above).
-    ${pkgs.procps}/bin/pkill -USR2 -x .waybar-wrapped || true
+    # Anchored ERE covers both comms: the wrapper-launched bar (comm
+    # `.waybar-wrapped`) and one the monitor-hotplug handler relaunched via
+    # `hyprctl dispatch exec waybar` (comm `waybar`).
+    ${pkgs.procps}/bin/pkill -USR2 -x '\.waybar-wrapped|waybar' || true
     bg="$HOME/.local/share/bg"
     [ -e "$bg" ] && ${pkgs.awww}/bin/awww img "$bg" || true
   '';
 in
 {
-  imports = [ ./gpg.nix ./media.nix ./texlive.nix ./librewolf.nix ./mc.nix ./mime.nix ./hyprland-workspaces.nix ./nvim.nix ];
+  imports = [ ./gpg.nix ./media.nix ./texlive.nix ./librewolf.nix ./mc.nix ./mime.nix ./hyprland-workspaces.nix ./nvim.nix ./dictionaries.nix ];
 
   # Put ~/.local/bin (the XDG user-bin dir) on PATH so hand-dropped scripts run
   # by name without wiring each through nix.
@@ -144,9 +147,8 @@ in
     # -p. Pins throwaway REPLs and new projects to one version across machines
     # (further steered by uv.toml below). Fetched on demand by uv, not Nix.
     UV_PYTHON = "3.14";
-    # psql / wget / readline configs, XDG-routed (the rc files are declared
+    # wget / readline configs, XDG-routed (the rc files are declared via
-    # via xdg.configFile below).
+    # xdg.configFile below).
-    PSQLRC = "${config.xdg.configHome}/psql/rc";
     WGETRC = "${config.xdg.configHome}/wget/wgetrc";
     INPUTRC = "${config.xdg.configHome}/readline/inputrc";
     # Rust/cargo: keep registry cache, git checkouts and `cargo install` bins
@@ -190,6 +192,9 @@ in
     unzip       # extract .zip (tools that shell out to it expect the binary)
     jq          # JSON on the command line (scripts, ad-hoc inspection)
     pv          # pipe progress meter (throughput, ETA on streamed data)
+    git-filter-repo  # `git filter-repo`: history rewriting (upstream's replacement
+                     # for `git filter-branch`); a standalone script git picks
+                     # up as a subcommand, so programs.git needs no config
     libreoffice
     grim        # screenshot capture (also used by the Print-key binds)
     slurp       # interactive region selector for grim
@@ -218,12 +223,6 @@ in
       python-preference = "managed"
     '';
 
-    # psql: unlimited, per-database history file (kept out of $HOME).
-    "psql/rc".text = ''
-      \set HISTFILE ${config.xdg.cacheHome}/psql/history-:DBNAME
-      \set HISTSIZE -1
-    '';
-
     # wget: keep its HSTS db in the cache dir, not ~/.
     "wget/wgetrc".text = ''
       hsts-file=${config.xdg.cacheHome}/wget/hsts
@@ -595,7 +594,8 @@ in
       };
 
       input = {
-        kb_layout = "de";
+        # Neutral default; set the real layout in your inventory (like console.keyMap).
+        kb_layout = lib.mkDefault "us";
         follow_mouse = 1;
         numlock_by_default = true;
       };
@@ -667,8 +667,8 @@ in
         # the ~/.local/share/bg symlink if it exists.
         "awww-daemon"
         "sh -c '[ -e \"$HOME/.local/share/bg\" ] && awww img \"$HOME/.local/share/bg\"'"
-        # re-push the wallpaper onto monitors connected after login (media.nix)
+        # re-push wallpaper + relaunch waybar on monitor add/remove (media.nix)
-        "wallpaper-hotplug"
+        "monitor-hotplug"
       ];
     };
   };

modules/media.nix

@@ -7,7 +7,7 @@
 # awww-daemon and the boot-time restore from that symlink run as Hyprland
 # `exec-once` (see home.nix).
 
-{ pkgs, ... }:
+{ pkgs, config, ... }:
 
 let
   # setbg: persist the choice as an XDG-data symlink, then set it live. Startup
@@ -21,15 +21,35 @@ let
   # awww-daemon paints only the outputs present when `awww img` last ran and does
   # not repaint a monitor hotplugged afterwards — it comes up on the fill color
   # (black), and a transparent foot on it then shows that black, not the
-  # wallpaper. Watch Hyprland's event socket and re-push the wallpaper (setbg
+  # wallpaper. Symmetric problem on real DP/HDMI unplug: Hyprland drops the
-  # with no arg → all current outputs) on each monitor-add. Hyprland emits both
+  # layer-shell surfaces on the surviving monitor and does not recreate them, so
-  # `monitoradded` and `monitoraddedv2`; match only the former so setbg fires
+  # its waybar and wallpaper vanish. Watch Hyprland's event socket and, on either
-  # once. Runs as a Hyprland exec-once (see home.nix).
+  # add or remove, re-push the wallpaper (setbg with no arg → all current
-  wallpaperHotplug = pkgs.writeShellScriptBin "wallpaper-hotplug" ''
+  # outputs) and fully relaunch waybar. A SIGUSR2 reload is not enough — it
+  # rereads config but does not recreate a bar Hyprland already tore down — so
+  # kill and restart, which enumerates the current outputs and draws a bar on
+  # each. The event flaps (several add/remove lines per plug); the loop is
+  # sequential so each pass converges to one waybar. Hyprland emits both
+  # `monitoradded` and `monitoraddedv2`; match only the non-v2 forms so each side
+  # fires once. Runs as a Hyprland exec-once (see home.nix).
+  hyprctl = "${config.wayland.windowManager.hyprland.finalPackage}/bin/hyprctl";
+  monitorHotplug = pkgs.writeShellScriptBin "monitor-hotplug" ''
     sock="''${XDG_RUNTIME_DIR}/hypr/''${HYPRLAND_INSTANCE_SIGNATURE}/.socket2.sock"
     ${pkgs.socat}/bin/socat -u UNIX-CONNECT:"$sock" - | while IFS= read -r line; do
       case "$line" in
-        "monitoradded>>"*) setbg ;;
+        "monitoradded>>"* | "monitorremoved>>"*)
+          sleep 1                                    # let Hyprland settle the new geometry
+          setbg                                      # re-push wallpaper to all current outputs
+          # Anchored ERE matching `comm` (max 15 chars): the bar launched via the
+          # home-manager wrapper reports comm `.waybar-wrapped` (arg[0] is still
+          # `waybar`), so a bare `-x waybar` never matches it and leaves a stale bar.
+          wb='\.waybar-wrapped|waybar'
+          ${pkgs.procps}/bin/pkill -x "$wb" || true  # relaunch waybar fresh (see comment)
+          i=0
+          while [ $i -lt 6 ] && ${pkgs.procps}/bin/pgrep -x "$wb" >/dev/null; do sleep 0.3; i=$((i+1)); done
+          ${pkgs.procps}/bin/pkill -9 -x "$wb" || true
+          ${hyprctl} dispatch exec waybar
+          ;;
       esac
     done
   '';
@@ -66,7 +86,7 @@ in
 
   home.packages = with pkgs; [
     setbg
-    wallpaperHotplug # re-push wallpaper to a hotplugged monitor (see comment above)
+    monitorHotplug  # re-push wallpaper + reload waybar on monitor add/remove (see comment above)
     awww            # wayland wallpaper daemon (setbg backend)
     wl-clipboard    # wl-copy, for the yank binds
     imagemagick     # `magick`: rotate/flip binds

modules/nixos.nix

@@ -5,7 +5,7 @@
 { config, lib, pkgs, ... }:
 
 {
-  imports = [ ./shutdown-debug.nix ./printing-scanning.nix ];
+  imports = [ ./shutdown-debug.nix ./printing-scanning.nix ./rebuild-diff.nix ];
 
   nix.settings.experimental-features = [ "nix-command" "flakes" ];
   # Deduplicate identical store paths via hardlinks.

modules/nvim.nix

@@ -1,8 +1,26 @@
 # Neovim, configured declaratively via nixvim. The editor — plugins, LSP,
 # completion, keymaps — is defined here and pinned by the flake lock; nothing is
-# downloaded at runtime, unlike an imperative distro (NvChad/LazyVim). The nixvim
+# downloaded at runtime. The nixvim home-manager module that provides
-# home-manager module that provides `programs.nixvim` is imported for consumers by
+# `programs.nixvim` is imported for consumers by `homeModules.default` in
-# `homeModules.default` in flake.nix, so this file only sets options.
+# flake.nix, so this file only sets options.
+#
+# Why this rather than a distro (LazyVim, NvChad, AstroNvim): those drive
+# lazy.nvim as a package manager, which git-clones plugins into
+# ~/.local/share/nvim on first launch and updates them in place. The editor's
+# actual contents would then live outside the flake — unpinned, unreproducible,
+# and invisible to a rollback.
+#
+# That choice has a price, and it is paid in ergonomics. A distro ships hundreds
+# of defaults other people already sanded smooth; this config does not. Rough
+# edges surface one at a time, mid-task, and each gets fixed by hand here (see
+# the `<leader>bd` and `<leader>Q` keymaps for two such fixes). Anyone extending
+# this should expect that cost rather than be surprised by it.
+#
+# The middle path stays open: the objection is to lazy.nvim as a *runtime*
+# package manager, not to a distro's ergonomics. Individual keymaps, option
+# sets, and plugin configurations can be lifted from LazyVim & co. into this
+# file, and nixvim installs any plugin set declaratively. Borrow freely — just
+# keep the installation declarative.
 #
 # Consumer knobs (the option-with-default contract): `local.nvim.enable` to opt
 # out wholesale, `local.nvim.colorscheme` to swap theme in one line, and
@@ -86,8 +104,8 @@ in
         scrolloff = 8;              # keep 8 lines of context around the cursor
 
         expandtab = true;           # spaces, not tabs
-        shiftwidth = 2;
+        shiftwidth = 4;
-        tabstop = 2;
+        tabstop = 4;
         smartindent = true;
 
         ignorecase = true;          # case-insensitive search…
@@ -162,10 +180,31 @@ in
         blink-cmp = {
           enable = true;
           settings = {
-            keymap.preset = "default";   # C-space open, C-y confirm, C-n/C-p move
+            # "enter" preset: <CR> accepts, Up/Down and C-n/C-p move, Tab is
+            # left to snippet jumping. Custom keys below merge over the preset.
+            keymap = {
+              preset = "enter";
+              # Vim's own ins-completion confirm key, kept alongside <CR>.
+              "<C-y>" = [ "select_and_accept" "fallback" ];
+              # Dismiss the menu and undo the auto_insert preview, staying in
+              # insert mode. `cancel` rather than the preset's `hide`, which
+              # would leave the previewed text in the buffer without the
+              # additionalTextEdits (imports) and snippet expansion that a real
+              # accept applies — a degraded accept nobody wants. This also
+              # matches builtin ins-completion, where C-e restores the typed
+              # text. With no menu open both keys fall back to their native
+              # meaning (Esc leaves insert mode).
+              "<C-e>" = [ "cancel" "fallback" ];
+              "<Esc>" = [ "cancel" "fallback" ];
+            };
             appearance.nerd_font_variant = "mono";
             sources.default = [ "lsp" "path" "snippets" "buffer" ];
-            completion.documentation.auto_show = true;
+            completion = {
+              documentation.auto_show = true;
+              # No item is selected until one is picked with Down/C-n, so <CR>
+              # inserts a newline unless a completion was deliberately chosen.
+              list.selection.preselect = false;
+            };
           };
         };
 
@@ -227,11 +266,24 @@ in
         };
       };
 
+      # Moodle/Mustache templates. nvim detects `.mustache` as filetype mustache
+      # but ships no syntax file for it, so the buffer renders as plain text.
+      # Tree-sitter is not an option here: the Handlebars grammar (glimmer)
+      # rejects mustache's argument-less sections, `{{{unescaped}}}`, partials
+      # and Moodle's `{{< parent }}` inheritance, and a single error node drops
+      # highlighting for the rest of the file. This plugin carries the syntax,
+      # indent and ftdetect scripts. nixpkgs marks it unfree only because
+      # upstream ships no license metadata; `allowUnfree` in modules/nixos.nix
+      # already covers it.
+      extraPlugins = [ pkgs.vimPlugins.vim-mustache-handlebars ];
+
       # Global (non-LSP) keymaps. Deliberately small — a starting point to grow.
       keymaps = [
         { mode = "n"; key = "<leader>w"; action = "<cmd>w<cr>"; options.desc = "Save"; }
         { mode = "n"; key = "<leader>q"; action = "<cmd>q<cr>"; options.desc = "Quit window"; }
-        { mode = "n"; key = "<leader>Q"; action = "<cmd>qa<cr>"; options.desc = "Quit all (exit nvim)"; }
+        # `confirm` prompts Save/Discard/Cancel per modified buffer rather than
+        # aborting with E37, so quitting never dead-ends and never writes silently.
+        { mode = "n"; key = "<leader>Q"; action = "<cmd>confirm qa<cr>"; options.desc = "Quit all (prompt to save)"; }
         # Restore the saved session for the current directory (persistence.nvim).
         { mode = "n"; key = "<leader>S"; action.__raw = "function() require('persistence').load() end"; options.desc = "Restore session"; }
         { mode = "n"; key = "<leader>e"; action = "<cmd>Neotree toggle<cr>"; options.desc = "File tree"; }
@@ -251,7 +303,26 @@ in
         # Buffer navigation (no bufferline: cycle with Shift-h/l, list via <leader>fb)
         { mode = "n"; key = "<S-l>"; action = "<cmd>bnext<cr>"; options.desc = "Next buffer"; }
         { mode = "n"; key = "<S-h>"; action = "<cmd>bprevious<cr>"; options.desc = "Prev buffer"; }
-        { mode = "n"; key = "<leader>bd"; action = "<cmd>bdelete<cr>"; options.desc = "Close buffer"; }
+        # Plain `:bdelete` closes the window when no other listed buffer is left
+        # for it to show, which with neo-tree open leaves a full-width tree.
+        # Point the window at another buffer (or a fresh empty one) first, so the
+        # layout survives; `confirm` prompts rather than failing when modified.
+        {
+          mode = "n";
+          key = "<leader>bd";
+          action.__raw = ''
+            function()
+              local cur = vim.api.nvim_get_current_buf()
+              local listed = vim.tbl_filter(
+                function(b) return vim.bo[b].buflisted end,
+                vim.api.nvim_list_bufs()
+              )
+              if #listed > 1 then vim.cmd('bprevious') else vim.cmd('enew') end
+              vim.cmd('confirm bdelete ' .. cur)
+            end
+          '';
+          options.desc = "Close buffer";
+        }
 
         # Terminal: toggle a horizontal or vertical split (toggleterm). Same key
         # hides it again. From inside the terminal, <C-w> drops to normal mode and

modules/rebuild-diff.nix

@@ -0,0 +1,83 @@
+# `nixos-diff`: after a rebuild, report (1) what packages changed and (2) whether the
+# change needs a reboot, a re-login, or nothing. NixOS keeps two markers —
+# /run/booted-system (what you booted) and /run/current-system (what the last `switch`
+# activated). A switch applies userland live, but:
+#   - the kernel, initrd, and kernel modules are frozen until the next BOOT — detected
+#     exactly, by comparing those store paths between the two systems;
+#   - session-mapped components (the Wayland compositor, GL stack, portals) a running
+#     graphical session keeps until you log out and back in — detected HEURISTICALLY,
+#     by matching changed package names against `local.rebuildDiff.reloginPackages`.
+# Generic and topology-free, so it rides in the baseline; disable with
+# `local.rebuildDiff.enable = false`.
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.local.rebuildDiff;
+  reloginPattern = lib.concatStringsSep "|" cfg.reloginPackages;
+
+  nixos-diff = pkgs.writeShellApplication {
+    name = "nixos-diff";
+    runtimeInputs = [ pkgs.nvd pkgs.coreutils pkgs.gnugrep ];
+    text = ''
+      booted=/run/booted-system
+      current=/run/current-system
+
+      # Package-level diff of the running system vs the activated one. Force colour
+      # (nvd auto-disables it when captured); only version parts are coloured, so the
+      # package-name grep below is unaffected.
+      diff=$(nvd --color always diff "$booted" "$current")
+      printf '%s\n' "$diff"
+
+      # Reboot (exact): kernel/initrd/modules only take effect on the next boot.
+      reboot=0
+      for c in kernel initrd kernel-modules; do
+        [ "$(readlink -f "$booted/$c" 2>/dev/null)" = "$(readlink -f "$current/$c" 2>/dev/null)" ] \
+          || reboot=1
+      done
+
+      # Re-login (heuristic): session-mapped components a running Wayland session
+      # keeps until you log out and back in.
+      relogin_hits=""
+      ${lib.optionalString (reloginPattern != "") ''
+        relogin_hits=$(printf '%s\n' "$diff" | grep -Ew "${reloginPattern}" || true)
+      ''}
+
+      echo
+      if [ "$reboot" -eq 1 ]; then
+        printf '>>> REBOOT needed (kernel/initrd/modules changed).\n'
+      elif [ -n "$relogin_hits" ]; then
+        printf '>>> RE-LOGIN recommended — session components changed:\n'
+        printf '%s\n' "$relogin_hits"
+      else
+        printf '>>> No reboot/re-login needed.\n'
+      fi
+    '';
+  };
+in
+{
+  options.local.rebuildDiff = {
+    enable = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = ''
+        Install `nixos-diff`: after a `nixos-rebuild switch`, print an `nvd` closure
+        diff of the running vs activated system plus a reboot / re-login / live verdict.
+      '';
+    };
+
+    reloginPackages = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ "mesa" "wayland" "hyprland" "xdg-desktop-portal" ];
+      description = ''
+        Whole-word package-name patterns matched against the diff; a match means a
+        running Wayland session should be restarted (re-login) to pick the change up —
+        the compositor, GL stack, and portals. Extend per host (e.g. a specific GPU
+        driver). Empty disables the re-login heuristic.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ nixos-diff pkgs.nvd ];
+  };
+}