Initial commit: krops-lamassu deployment template

NixOS deployment template for Lamassu Bitcoin ATM server using
nix-bitcoin and krops.

Features:
- Lamassu server with PostgreSQL and auto-generated secrets
- TLS certificates (self-signed)
- Test VM for local development
- Template structure for easy customization

shell.nix

@@ -0,0 +1,18 @@
+# Development shell for nix-bitcoin deployment
+#
+# Enter the shell with: nix-shell
+#
+# This provides all tools needed for deployment and management.
+
+let
+  nix-bitcoin = toString (import ./config/nix-bitcoin-release.nix);
+in
+  import "${nix-bitcoin}/helper/makeShell.nix" {
+    configDir = ./config;
+    shellVersion = "0.0.85";
+
+    # Set this to modify your shell
+    # extraShellInitCmds = pkgs: ''
+    #   echo "nix-bitcoin development shell"
+    # '';
+  }