chore: initial commit

Add project scaffolding: CLAUDE.md, PLAN.md, README.md, flake.nix, and go.mod.

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

flake.nix

@@ -0,0 +1,28 @@
+{
+  description = "Oubliette - SSH Honeypot";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      supportedSystems = [ "x86_64-linux" "aarch64-linux" ];
+      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
+    in
+    {
+      devShells = forAllSystems (system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          default = pkgs.mkShell {
+            buildInputs = [
+              pkgs.go
+              pkgs.govulncheck
+              pkgs.golangci-lint
+            ];
+          };
+        });
+    };
+}