feat: switch from flake-parts & devenv to rensa + add nixtest

nix/repo/docs.nix

@@ -0,0 +1,61 @@
+{
+  inputs,
+  cell,
+  ...
+}: let
+  inherit (inputs) doclib;
+  inherit (cell) nixlets;
+in
+  (doclib.mkDocs {
+    docs."default" = {
+      base = "${inputs.self}";
+      path = "${inputs.self}/docs";
+      material = {
+        enable = true;
+        colors = {
+          primary = "blue";
+          accent = "light blue";
+        };
+        umami = {
+          enable = true;
+          src = "https://analytics.tf/umami";
+          siteId = "a4181010-317a-45e3-978c-5d07a93e0cd2";
+          domains = ["nixlets.projects.tf"];
+        };
+      };
+      dynamic-nav = {
+        enable = true;
+        files."Nixlets Values" = builtins.map (val: {${val.name} = val.mkDocs {};}) (builtins.attrValues nixlets);
+      };
+      config = {
+        site_name = "Nixlets";
+        site_url = "https://nixlets.projects.tf";
+        repo_name = "TECHNOFAB/nixlets";
+        repo_url = "https://gitlab.com/TECHNOFAB/nixlets";
+        extra_css = ["style.css"];
+        theme = {
+          logo = "images/logo.svg";
+          icon.repo = "simple/gitlab";
+          favicon = "images/logo.svg";
+        };
+        nav = [
+          {"Introduction" = "index.md";}
+          {"Creating Nixlets" = "creation.md";}
+          {"Packaging" = "packaging.md";}
+          {"Usage" = "usage.md";}
+          {"Secrets" = "secrets.md";}
+        ];
+        markdown_extensions = [
+          {
+            "pymdownx.highlight".pygments_lang_class = true;
+          }
+          "pymdownx.inlinehilite"
+          "pymdownx.snippets"
+          "pymdownx.superfences"
+          "fenced_code"
+          "admonition"
+        ];
+      };
+    };
+  })
+  .packages