Restructure networking configuration to per-machine modules

- Move networking configs to modules/network/ directory
- Create network-<machine-name>.nix files for each machine
- Add common.nix for shared networking configuration
- Update import paths in machine configurations
- Reduce duplication by using common networking settings

Network modules:
- modules/network/common.nix: Shared settings (nftables, SSH, tailscale)
- modules/network/network-congenital-optimist.nix: Workstation specific
- modules/network/network-sleeper-service.nix: File server specific

modules/system/network.nix

@@ -1,26 +0,0 @@
-{ config, pkgs, ... }: {
-  # Network configuration
-  networking = {
-    hostName = "congenital-optimist";
-    hostId = "8425e349";
-    networkmanager.enable = true;
-    nftables.enable = true;
-    
-    # Firewall configuration
-    firewall = {
-      enable = true;
-      allowedTCPPorts = [ 22 ];
-      allowedUDPPorts = [ 22 ];
-    };
-  };
-
-  # VPN and remote access
-  services.tailscale.enable = true;
-  services.openssh.enable = true;
-
-  # ZFS services
-  services.zfs = {
-    autoScrub.enable = true;
-    trim.enable = true;
-  };
-}

modules/system/transmission.nix

@@ -0,0 +1,20 @@
+{ config, pkgs, ... }:
+
+{
+  services.transmission = {
+    enable = true;
+    user = "geir";
+    group = "users";
+    #home = "/mnt/storage/";
+    settings.rpc-port = 9091;
+    settings.rpc-bind-address = "0.0.0.0";
+    #openRPCPort = true;
+    downloadDirPermissions = "770";
+    settings = {
+      download-dir = "/mnt/storage";
+      #rpc-whitelist-enabled = true;
+      rpc-whitelist = "127.0.0.1,10.0.0.*,100.*.*.*";
+      rpc-host-whitelist = "congenital-optimist,localhost";
+    };
+  };
+}