feat: nomarchy.lib.mkFlake — one-call downstream wrapper + hardware profiles

Downstream users now own only system.nix and home.nix; their flake.nix is
generated once from the template and never hand-edited. mkFlake (lib.nix)
wires both layers and maps hardwareProfile = "<name>" to nixos-hardware
modules (new input, pinned here, nixpkgs follows ours; unknown names fail
with did-you-mean suggestions). Flake checks evaluate the template through
mkFlake — including a real profile — so drift fails `nix flake check`.

Also from the live-VM testing session: install the home-manager CLI in the
live ISO and pin flake inputs transitively (offline theme switching needs
stylix's own inputs too), plus swww→awww doc updates.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -23,7 +23,7 @@ partial.
 │    Stylix → GTK, Qt, cursors, fonts                                      │
 └───────────────────────────────────┬──────────────────────────────────────┘
                                     ▼
-              wallpaper via swww (the one runtime piece:                    
+              wallpaper via awww (the one runtime piece:                    
               applied post-switch + at session start, `bg next` cycles)     
 ```
 
@@ -34,6 +34,7 @@ Flat on purpose. Two module trees, one options file each, no hidden layers.
 ```
 .
 ├── flake.nix                      # inputs + the downstream API (exports below)
+├── lib.nix                        # nomarchy.lib.mkFlake — one-call downstream wrapper
 ├── theme-state.json               # ★ THE single source of truth (git-tracked!)
 ├── themes/                        # 21 presets: <slug>.json + optional <slug>/ assets
 │   ├── nord.json                  #   palette (required, works alone)
@@ -94,8 +95,30 @@ mkdir my-machine && cd my-machine
 nix flake init -t github:YOUR-USER/nomarchy
 ```
 
-You own three files: `system.nix`, `home.nix`, and **your own
-`theme-state.json`**. Two deliberately separate rebuild paths:
+You own two files day-to-day: `system.nix` and `home.nix` (plus
+`theme-state.json`, written by the CLI). Your `flake.nix` is set up once —
+later by the installer — and never hand-edited; it's a single call:
+
+```nix
+outputs = { nomarchy, ... }:
+  nomarchy.lib.mkFlake {
+    src = ./.;
+    username = "me";
+    hardwareProfile = "framework-13-7040-amd"; # optional, nixos-hardware name
+  };
+```
+
+| `mkFlake` arg | Default | Purpose |
+|---|---|---|
+| `src` | — (required) | Your flake directory (`./.`) |
+| `username` | — (required) | Login name; flows into `system.nix` and names the HM config |
+| `hardwareProfile` | `null` | A [nixos-hardware](https://github.com/NixOS/nixos-hardware) module name (pinned + tested by Nomarchy; unknown names fail with suggestions) |
+| `system` | `"x86_64-linux"` | Platform |
+
+(Power users can skip `mkFlake` and wire `nixosModules.nomarchy` /
+`homeModules.nomarchy` / `overlays.default` by hand — the wrapper is sugar.)
+
+Two deliberately separate rebuild paths:
 
 ```sh
 sudo nixos-rebuild switch --flake .#default   # system: rare
@@ -141,9 +164,10 @@ fonts. No runtime patching means no partial states, and `home-manager
 generations` is also your theme history. Waybar even restyles in place: it
 re-reads `style.css` when the symlink flips.
 
-The **wallpaper** is the one runtime piece (swww is imperative; nothing in
-Nix consumes the path): applied at session start and after every switch via
-a tiny activation hook, cycled instantly with `bg next`.
+The **wallpaper** is the one runtime piece (awww — nixpkgs' swww — is
+imperative; nothing in Nix consumes the path): applied at session start and
+after every switch via a tiny activation hook, cycled instantly with
+`bg next`.
 
 ### Per-theme app assets (`themes/<slug>/`)
 
@@ -192,6 +216,6 @@ workspaces · `Print` region screenshot.
   re-copy on every state write is the main eval tax), then pre-built theme
   variants if still needed
 - Plymouth + SDDM/greeter theming from the same JSON
-- Interactive installer on the live ISO (disko BTRFS+LUKS, hardware
-  profiles) — port from old_distro
+- Interactive installer on the live ISO (disko BTRFS+LUKS, DMI →
+  `hardwareProfile` autodetection feeding `mkFlake`) — port from old_distro
 - `hyprlock`/`hypridle`, swayosd, launch-or-focus UX scripts