Added comments to flake

flake.nix

@@ -1,24 +1,45 @@
 {
+  # Human-readable description of what this flake produces
   description = "Minimal NixOS Docker Swarm server";
 
+  # Inputs — external dependencies that this flake depends on
+  # Each input is fetched and locked in flake.lock for reproducibility
   inputs = {
+    # The NixOS package collection, pinned to the 25.05 release branch
+    # This is the source of all packages and NixOS modules used in configuration.nix
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
   };
 
+  # Outputs — what this flake produces (NixOS configs, formatter, etc.)
+  # self = this flake's source tree, nixpkgs = the input defined above
+  # @inputs captures all inputs for passing to modules via specialArgs
   outputs = { self, nixpkgs, ... }@inputs: {
+    # NixOS system configuration named "server"
+    # Referenced with --flake .#server in nixos-rebuild commands
     nixosConfigurations.server = nixpkgs.lib.nixosSystem {
+      # Target architecture — change to aarch64-linux for ARM servers
       system = "x86_64-linux";
+      # Pass all flake inputs into modules so they can access them via `inputs` arg
       specialArgs = { inherit inputs; };
+      # List of NixOS module files that make up the system configuration
       modules = [
+        # Main system configuration (packages, services, firewall, etc.)
         ./configuration.nix
+        # Inline module for flake-specific Nix settings
         {
+          # Enable experimental Nix features required for flakes and nix command
           nix.settings.experimental-features = [ "nix-command" "flakes" ];
+          # Register this flake's nixpkgs input as the system-wide nixpkgs registry
+          # This lets you run `nix run nixpkgs#htop` without needing channels
           nix.registry.nixpkgs.flake = nixpkgs;
+          # Point legacy Nix tools (nix-build, nix-shell) at this flake's nixpkgs
+          # Eliminates the need for /nix/var/nix/profiles/per-user/root/channels
           nix.nixPath = [ "nixpkgs=flake:nixpkgs" ];
         }
       ];
     };
 
+    # Formatter for `nix fmt` — auto-formats .nix files using the official RFC 166 style
     formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt-rfc-style;
   };
 }