Add NixOS support with configuration module

- Add nixos/kawa.nix module for NixOS integration
- Add flake.nix for Nix flakes support
- Update setup script to detect and handle NixOS
- Include NATS, Syncthing, and Tailscale configuration
- Add parameters for Headscale connection

nixos/default.nix

@@ -0,0 +1,18 @@
+# KAWA OS - Configuration par défaut
+# Usage: import dans configuration.nix
+
+{ config, lib, pkgs, ... }:
+
+{
+  imports = [
+    ./kawa.nix
+  ];
+  
+  services.kawa = {
+    enable = true;
+    autoConnect = true;
+    enableNats = true;
+    enableSyncthing = true;
+    enableOllama = false; # Activer si GPU disponible
+  };
+}

nixos/kawa.nix

@@ -0,0 +1,148 @@
+# KAWA OS - Module NixOS
+# Configuration automatique pour rejoindre le mesh KAWA
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.kawa;
+in
+{
+  options.services.kawa = {
+    enable = mkEnableOption "KAWA mesh network";
+    
+    hostname = mkOption {
+      type = types.str;
+      default = "";
+      description = "Hostname personnalisé pour le nœud KAWA";
+    };
+    
+    headscaleUrl = mkOption {
+      type = types.str;
+      default = "https://headscale.du-senegal.com";
+      description = "URL du serveur Headscale";
+    };
+    
+    headscaleFallback = mkOption {
+      type = types.str;
+      default = "http://141.94.23.212";
+      description = "URL de fallback du serveur Headscale";
+    };
+    
+    authKey = mkOption {
+      type = types.str;
+      default = "f43f36ef159b3df799eb316b81bdac1b415c7cc2add174d0";
+      description = "Clé d'authentification Headscale";
+    };
+    
+    autoConnect = mkOption {
+      type = types.bool;
+      default = true;
+      description = "Connexion automatique au mesh au démarrage";
+    };
+    
+    # Services KAWA
+    enableNats = mkOption {
+      type = types.bool;
+      default = true;
+      description = "Activer le client NATS";
+    };
+    
+    enableSyncthing = mkOption {
+      type = types.bool;
+      default = true;
+      description = "Activer Syncthing pour la synchronisation";
+    };
+    
+    enableOllama = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Activer Ollama pour l'inférence locale";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    # Tailscale configuration
+    services.tailscale = {
+      enable = true;
+      extraUpFlags = [
+        "--login-server=${cfg.headscaleUrl}"
+        "--authkey=${cfg.authKey}"
+        "--hostname=${if cfg.hostname != "" then cfg.hostname else "kawa-${config.networking.hostName}"}"
+      ];
+    };
+    
+    # NATS client
+    services.nats = mkIf cfg.enableNats {
+      enable = true;
+      server = "100.64.0.1:4222";
+    };
+    
+    # Syncthing
+    services.syncthing = mkIf cfg.enableSyncthing {
+      enable = true;
+      user = "kawa";
+      group = "kawa";
+      config = {
+        folders = {
+          "kawa-memory" = {
+            path = "/home/kawa/.local/share/kawa/memory";
+            devices = [ "vps-7ed4abb0" ];
+          };
+          "kawa-workspace" = {
+            path = "/home/kawa/.local/share/kawa/workspace";
+            devices = [ "vps-7ed4abb0" ];
+          };
+          "kawa-forge" = {
+            path = "/home/kawa/.local/share/kawa/forge";
+            devices = [ "vps-7ed4abb0" ];
+          };
+        };
+      };
+    };
+    
+    # Ollama (optionnel)
+    services.ollama = mkIf cfg.enableOllama {
+      enable = true;
+      acceleration = false; # À activer si GPU disponible
+    };
+    
+    # Utilisateur KAWA
+    users.users.kawa = {
+      isNormalUser = true;
+      description = "KAWA Node User";
+      extraGroups = [ "wheel" "networkmanager" "tailscale" ];
+    };
+    
+    # Firewall
+    networking.firewall = {
+      allowedTCPPorts = [ 22 4222 22000 ];
+      allowedUDPPorts = [ 41641 22000 ];
+      trustedInterfaces = [ "tailscale0" ];
+    };
+    
+    # Environment packages
+    environment.systemPackages = with pkgs; [
+      tailscale
+      natscli
+      syncthing
+      git
+      curl
+      wget
+    ];
+    
+    # Systemd service pour la connexion automatique
+    systemd.services.kawa-connect = mkIf cfg.autoConnect {
+      description = "KAWA Mesh Auto-Connect";
+      after = [ "network-online.target" "tailscale.service" ];
+      wants = [ "network-online.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        Type = "oneshot";
+        ExecStart = "${pkgs.tailscale}/bin/tailscale up --login-server=${cfg.headscaleUrl} --authkey=${cfg.authKey} --force-reauth";
+        RemainAfterExit = true;
+      };
+    };
+  };
+}