Add modular service configuration with SearXNG and Nginx

- Create modules/ directory with reusable NixOS modules
- Add system module for main user configuration
- Add podman module for rootless container support
- Add nginx module with automatic Let's Encrypt SSL
- Add searxng module with Anubis AI firewall protection
- Configure SearXNG at search.ashisgreat.xyz
- Enable nginx reverse proxy with HTTPS

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/podman.nix

@@ -0,0 +1,32 @@
+# Podman Module
+# Provides: Rootless container runtime configuration
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.myModules.podman;
+  mainUser = config.myModules.system.mainUser;
+in
+{
+  options.myModules.podman = {
+    enable = lib.mkEnableOption "Podman container runtime";
+  };
+
+  config = lib.mkIf cfg.enable {
+    virtualisation.podman = {
+      enable = true;
+      dockerCompat = true;
+      defaultNetwork.settings.dns_enabled = true;
+    };
+
+    # Enable OCI containers (quadlet/podman containers)
+    virtualisation.oci-containers.backend = "podman";
+
+    # Give main user access to podman
+    users.users.${mainUser}.extraGroups = [ "podman" ];
+  };
+}