build(nix): one tools-only flake at the repo root

.cspell.json

@@ -51,11 +51,13 @@
     "artifactgc",
     "clientset",
     "clusterworkflowtemplate",
+    "codegen",
     "Creds",
     "cronworkflow",
     "cronworkflows",
     "cwft",
     "daemoned",
+    "direnv",
     "featuregen",
     "ffsv",
 	"gcflags",
@@ -72,6 +74,7 @@
 	"multiclient",
 	"mainctrfs",
     "mypassword",
+    "nixpkgs",
     "nonroot",
     "podpriority",
     "promtail",
@@ -89,6 +92,7 @@
     "workflowkey",
     "workflowtemplate",
     "workflowtemplates",
+    "wslconfig",
     "zstd"
   ]
 }

.envrc

@@ -0,0 +1,9 @@
+# Enter the development shell automatically on `cd`, for anyone with direnv
+# installed (https://direnv.net). `direnv allow` once to opt in.
+#
+# Install nix-direnv (https://github.com/nix-community/nix-direnv) too: it caches
+# the shell so `cd` is instant and stops the garbage collector from throwing the
+# tools away.
+#
+# Without direnv, run `nix develop` by hand instead.
+use flake

.gitignore

@@ -18,7 +18,6 @@ debug.test
 git-ask-pass.sh
 *.iml
 /coverage.out
-.envrc
 /.vendor-new
 /kustomize
 /workflow-controller
@@ -57,11 +56,8 @@ result
 /ui/playwright-report/
 /ui/test-results/
 /ui/e2e/.auth/
-.devenv
-.devenv.flake.nix
+# direnv's cache of the nix devShell (see .envrc)
+.direnv/
 .*-vendor
 proto_vendor
 .github.com
-.go/
-.goenv/
-.gocache/

.markdownlint.yaml

@@ -6,3 +6,9 @@ MD007:
 MD024:
   siblings_only: true
 MD034: false
+# Rules added after markdownlint-cli 0.33, which the docs have never been
+# written to. Turning either on is a docs change, not a tooling one.
+# link text should be descriptive, i.e. not "here" or "link"
+MD059: false
+# table pipes should line up
+MD060: false