refactor: reorganize, add package (opencode, osgrep, beads), add ai agent shell

hosts/dev-vm.nix

@@ -0,0 +1,51 @@
+{ lib, pkgs, ... }: {
+  networking.hostName = "dev-vm";
+  # Set the baseline NixOS release used for stateful data; bump on rebuilds.
+  system.stateVersion = lib.mkDefault "24.05";
+
+  # Boot loader configuration for VM
+  boot.loader.grub.enable = lib.mkDefault true;
+  boot.loader.grub.device = lib.mkDefault "/dev/vda";
+
+  # Root filesystem configuration for VM
+  fileSystems."/" = lib.mkDefault {
+    device = "/dev/vda1";
+    fsType = "ext4";
+  };
+
+  environment.systemPackages = with pkgs; [
+    # Core utilities
+    coreutils
+    ast-grep
+    ripgrep
+    bat
+    tree
+    zip
+    unzip
+    jq
+    psmisc # provides killall and friends
+    gh
+    tree-sitter
+
+    # System monitoring & debugging tools
+    htop # Process viewer
+    iotop # I/O monitoring
+    lsof # List open files
+    strace # System call tracing
+    ltrace # Library call tracing
+    gdb # GNU debugger
+    tcpdump # Network packet analyzer
+    ncdu # Disk usage analyzer
+  ];
+
+  services.qemuGuest.enable = true;
+
+  services.openssh.openFirewall = false;
+
+  networking.firewall = {
+    allowedTCPPorts = [ ];
+    interfaces."tailscale0".allowedTCPPorts = [ 22 ];
+  };
+
+  imports = [ ../modules/nixos/virtualization.nix ];
+}