refactor(nix): use flake-parts (#642)

refactor(nix): split into flake parts module and add shell.nix

chore: add prettier to treefmt and pin version

chore(nix): add prettier exclude

chore(nix): bump pnpm to v10.18.2

feat(nix): add overlay for nodejs

feat(nix): add overlay for nodejs

chore: consolidate .editorconfig

shell.nix

@@ -0,0 +1,12 @@
+(import (
+  let
+    lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+    nodeName = lock.nodes.root.inputs.flake-compat;
+  in
+  fetchTarball {
+    url =
+      lock.nodes.${nodeName}.locked.url
+        or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.${nodeName}.locked.rev}.tar.gz";
+    sha256 = lock.nodes.${nodeName}.locked.narHash;
+  }
+) { src = ./.; }).shellNix