Add configurable mode option for development/production

- Add services.lamassu-server.mode option (default: development)
- NODE_ENV is now set based on mode in all services
- Development mode uses port 3001 for admin UI registration URLs
- Production mode uses standard HTTPS port (443)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

modules/lamassu-lnbits.nix

@@ -9,7 +9,7 @@ let
 
   # Shared environment variables for both services
   commonEnv = {
-    NODE_ENV = "production";
+    NODE_ENV = cfg.mode;
     LOG_LEVEL = cfg.logLevel;
     HOSTNAME = cfg.hostname;
 
@@ -117,6 +117,15 @@ in
       description = "Logging level for lamassu-server";
     };
 
+    mode = mkOption {
+      type = types.enum [ "production" "development" ];
+      default = "development";
+      description = ''
+        Run in production or development mode.
+        Development mode uses port 3001 for admin UI registration URLs.
+      '';
+    };
+
     skip2FA = mkOption {
       type = types.bool;
       default = true;
@@ -270,6 +279,8 @@ in
         CI = "true";
         CC = "${pkgs.stdenv.cc}/bin/cc";
         CXX = "${pkgs.stdenv.cc}/bin/c++";
+        # Use content-addressable store to reduce disk usage
+        npm_config_cache = "${cfg.dataDir}/.npm-cache";
       };
 
       serviceConfig = {
@@ -285,6 +296,8 @@ in
         ProtectHome = true;
         NoNewPrivileges = true;
         ReadWritePaths = [ cfg.dataDir ];
+        # node-gyp needs writable /tmp for native module compilation
+        PrivateTmp = true;
       };
 
       script = ''
@@ -398,6 +411,7 @@ in
         export POSTGRES_HOST="127.0.0.1" POSTGRES_PORT="5432"
         export POSTGRES_DB="${cfg.database.name}" POSTGRES_USER="${cfg.database.user}" POSTGRES_PASSWORD="$DB_PASSWORD"
         export HOSTNAME="${cfg.hostname}" SKIP_2FA="${if cfg.skip2FA then "true" else "false"}"
+        export NODE_ENV="${cfg.mode}"
         sudo -E -u ${cfg.user} ${pkgs.nodejs_22}/bin/node ${cfg.dataDir}/source/packages/server/bin/lamassu-register "$@"
       '')
     ];