feat(slack-cli): add slack-cli package and enable on work MacBook

Add Python-based slack-cli package that reads Slack messages from local
Chromium IndexedDB cache. Includes pinned dependencies for dfindexeddb,
python-snappy, and zstd. Enable on mac-va-mbp-work home config.

homes/aarch64-darwin/evanreichard@mac-va-mbp-work/default.nix

@@ -57,6 +57,7 @@ in
     # colima
     docker
     keycastr
+    reichard.slack-cli
     _1password-cli
   ];
 }

packages/slack-cli/default.nix

@@ -0,0 +1,90 @@
+{ lib
+, fetchgit
+, fetchurl
+, python312
+, snappy
+,
+}:
+
+let
+  pythonPackages = python312.pkgs;
+
+  # ── Python Dependency Overrides ──────────────────────────────
+  #
+  # dfindexeddb pins python-snappy==0.6.1 and zstd==1.5.5.1.
+  # nixpkgs ships newer versions, so we build the exact pins
+  # from PyPI source tarballs.
+
+  python-snappy = pythonPackages.buildPythonPackage rec {
+    pname = "python-snappy";
+    version = "0.6.1";
+    format = "setuptools";
+
+    src = fetchurl {
+      url = "https://files.pythonhosted.org/packages/98/7a/44a24bad98335b2c72e4cadcdecf79f50197d1bab9f22f863a274f104b96/python-snappy-0.6.1.tar.gz";
+      hash = "sha256-tqEHqwYgasxTWdTFYyvZsi1EhwKnmzFpsMYuD7gIuyo=";
+    };
+
+    buildInputs = [ snappy ];
+
+    doCheck = false;
+  };
+
+  zstd-python = pythonPackages.buildPythonPackage rec {
+    pname = "zstd";
+    version = "1.5.5.1";
+    format = "setuptools";
+
+    src = fetchurl {
+      url = "https://files.pythonhosted.org/packages/source/z/zstd/zstd-1.5.5.1.tar.gz";
+      hash = "sha256-HvmAq/Dh4HKwKNLXbvlbR2YyZRyWIlzzC2Gcbu9iVnI=";
+    };
+
+    doCheck = false;
+  };
+
+  dfindexeddb = pythonPackages.buildPythonPackage rec {
+    pname = "dfindexeddb";
+    version = "20260210";
+    format = "setuptools";
+
+    src = fetchurl {
+      url = "https://files.pythonhosted.org/packages/source/d/dfindexeddb/dfindexeddb-20260210.tar.gz";
+      hash = "sha256-4ahEe4Lpoh0oqGR6kI7J1HEGfvKVEzu3qQ+3ykgFd/Y=";
+    };
+
+    propagatedBuildInputs = [
+      python-snappy
+      zstd-python
+    ];
+
+    doCheck = false;
+  };
+
+in
+pythonPackages.buildPythonApplication {
+  pname = "slack-cli";
+  version = "0.1.0";
+  format = "pyproject";
+
+  src = fetchgit {
+    url = "https://gitea.va.reichard.io/evan/slack-cli.git";
+    rev = "f49c944efe96ee9379f519e93100b4601b6b1afa";
+    hash = "sha256-XIifH3PlS9ZPlqZ+h2jGnvEOMciuPmR57CppMVSVL6M=";
+  };
+
+  build-system = [ pythonPackages.setuptools ];
+
+  dependencies = [ dfindexeddb ];
+
+  doCheck = false;
+
+  meta = {
+    description = "Read Slack messages from local Chromium IndexedDB cache";
+    homepage = "https://gitea.va.reichard.io/evan/slack-cli";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ evanreichard ];
+    mainProgram = "slack-cli";
+    platforms = lib.platforms.darwin;
+  };
+}