feat: add a fmt github action

.github/workflows/fmt.yml

@@ -0,0 +1,32 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  fmt:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: DeterminateSystems/nix-installer-action@main
+
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+
+      - name: Check formatting
+        run: nix fmt -- --fail-on-change
+
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: DeterminateSystems/nix-installer-action@main
+
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+
+      - name: Run nix flake check
+        run: nix flake check

README.md

@@ -51,14 +51,17 @@ just bootstrap-flash /dev/sdX
 ## Adding a New Host
 
 1. Run the new-host command:
+
    ```bash
    just new-host <hostname> <username>
    ```
+
    This creates:
    - `hosts/<hostname>/` directory
    - `secrets/hosts/<hostname>/` with SSH keys
 
 2. Add host configuration in `hosts/default.nix`:
+
    ```nix
    <hostname> = mkSystem {
      hostname = "<hostname>";
@@ -72,6 +75,7 @@ just bootstrap-flash /dev/sdX
    - Other host-specific modules as needed
 
 4. Generate hardware config:
+
    ```bash
    just factor <hostname>
    # Or for remote:
@@ -120,6 +124,7 @@ just age -e <file> -o <output.age>
 ### Formatting
 
 Code is formatted using `treefmt-nix` with:
+
 - **alejandra** - Nix formatter
 - **deadnix** - Remove unused Nix code
 - **statix** - Nix linter

modules/desktop/dms/bar.nix

@@ -76,9 +76,11 @@
     {
       id = "secondary-left";
       name = "Secondary Bar (Left)";
-      screenPreferences = builtins.map (monitor: {
-        inherit (monitor) name;
-      }) leftMonitors;
+      screenPreferences =
+        builtins.map (monitor: {
+          inherit (monitor) name;
+        })
+        leftMonitors;
       showOnLastDisplay = false;
       leftWidgets = [];
       centerWidgets = [];
@@ -92,9 +94,11 @@
     {
       id = "secondary-right";
       name = "Secondary Bar (Right)";
-      screenPreferences = builtins.map (monitor: {
-        inherit (monitor) name;
-      }) rightMonitors;
+      screenPreferences =
+        builtins.map (monitor: {
+          inherit (monitor) name;
+        })
+        rightMonitors;
       showOnLastDisplay = false;
       leftWidgets = [
         "workspaceSwitcher"