Convert to nix flake; fix systemd service to use nix run

- Add flake.nix with nixos-unstable nixpkgs, devShell and slopbot package
- Add flake.lock
- Update .envrc to 'use flake .'
- Update slopbot.service: use 'nix run' instead of nix-shell, remove
  broken sandbox options (ProtectHome, InaccessiblePaths, ProtectSystem,
  ReadOnlyPaths, ReadWritePaths, PrivateTmp) that block nix store access
- Delete shell.nix
- Add 'result' to .gitignore
- Restore openai to requirements.txt (was accidentally dropped)

1 files changed, 27 insertions, 0 deletions

diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..94e0bfb
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1778869304,
+        "narHash": "sha256-30sZNZoA1cqF5JNO9fVX+wgiQYjB7HJqqJ4ztCDeBZE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "d233902339c02a9c334e7e593de68855ad26c4cb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}