feat: implement SSH honeypot server with auth and config

Add core SSH server with password authentication, per-IP failure
tracking, credential memory with TTL, and static credential support.
Includes TOML config loading with validation, Ed25519 host key
auto-generation, and a Nix package output.

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

flake.nix

@@ -11,6 +11,24 @@
       forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
     in
     {
+      packages = forAllSystems (system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          default = pkgs.buildGoModule {
+            pname = "oubliette";
+            version = "0.1.0";
+            src = ./.;
+            vendorHash = "sha256-z/E1ZDfedOxI8CSUfcpFGYX0SrdcnAYuu2p0ATozDaA=";
+            subPackages = [ "cmd/oubliette" ];
+            meta = {
+              description = "SSH honeypot";
+              mainProgram = "oubliette";
+            };
+          };
+        });
+
       devShells = forAllSystems (system:
         let
           pkgs = nixpkgs.legacyPackages.${system};