vault-cli: extract to standalone repo, add flake.nix, move one-off scripts to scripts/one-off/

flake.nix

@@ -0,0 +1,33 @@
+{
+  description = "vault CLI + Librarian tooling for Ryan's R/J/F/I Obsidian vault";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      systems = [ "x86_64-linux" "aarch64-linux" ];
+      forAllSystems = nixpkgs.lib.genAttrs systems;
+    in
+    {
+      packages = forAllSystems (system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+          vault-cli = pkgs.callPackage ./package.nix { };
+        in
+        {
+          default = vault-cli;
+          vault-cli = vault-cli;
+        });
+
+      # Convenience module for consumers (e.g. nixos-config) that just want
+      # `vault` on $PATH for hosts playing a vault role. Mirrors the shape
+      # nixos-config's modules/hosts/core/vault.nix expects: import this and
+      # add `environment.systemPackages = [ pkgs.vault-cli ]` (or reference
+      # `self.packages.${system}.default` directly via a flake input).
+      nixosModules.default = { pkgs, ... }: {
+        environment.systemPackages = [ self.packages.${pkgs.system}.default ];
+      };
+    };
+}