fix: resolve code quality issues, add CI, and improve maintainability

- Remove useless nixConfig block (cache.nixos.org is default)
- Remove manual container-use override; let blueprint auto-discover it
- Add nixosModules.default so README example works
- Fix default launcher: use correct parameterized flake URL
- Replace deprecated sha256 with hash in goose-cli fetchers
- Fix LIBCLANG_PATH to include /lib subdirectory for libclang.so
- Drop --release from goose-cli tests (faster, more debug info)
- Use builtins.toFile in flake-inputs to avoid ARG_MAX risk
- Add lib.warn when overlay has no packages for a system
- Add passthru.updateScript to goose-cli, container-use, skillsmcp
- Fix skillsmcp version to 0.2.0+unstable (pinned to commit, not tag)
- Replace with lib; with explicit references in all meta blocks
- Add update.py script for goose-cli (referenced in AGENTS.md)
- Expand .gitignore with result-* and .direnv/
- Add GitHub Actions CI workflow (nix flake check + build)

packages/skillsmcp/package.nix

@@ -6,7 +6,9 @@
 
 python3Packages.buildPythonApplication rec {
   pname = "skillsmcp";
-  version = "0.2.0";
+  # Pinned to a commit rather than a release tag because upstream
+  # has not yet published a tagged release containing all features.
+  version = "0.2.0+unstable";
   pyproject = true;
 
   src = fetchFromGitHub {
@@ -25,17 +27,27 @@ python3Packages.buildPythonApplication rec {
     python3Packages.pyyaml
   ];
 
-  # Disable all checks to avoid version issues
+  # Tests fail due to version-string expectations baked into the upstream
+  # source (pinned to a commit rather than a release tag). The import
+  # check below still verifies the module loads correctly.
   doCheck = false;
   pythonImportsCheck = [ "skillsmcp" ];
 
-  passthru.category = "MCP Servers";
+  passthru = {
+    category = "MCP Servers";
+    updateScript = [
+      "nix-update"
+      "--flake"
+      ".#skillsmcp"
+      "--version=branch=main"
+    ];
+  };
 
-  meta = with lib; {
+  meta = {
     description = "MCP server that exposes Agent Skills to AI agents via the Model Context Protocol";
     homepage = "https://github.com/aviddiviner/skillsmcp";
-    license = licenses.mit;
+    license = lib.licenses.mit;
     mainProgram = "skillsmcp";
-    platforms = platforms.all;
+    platforms = lib.platforms.all;
   };
 }