feat(users/Profpatsch/struct-edit): initial version

A take at a TUI-based structural editor, which should eventually read
a type definition of a structure and some values, and build a GUI to
edit it.

So far you can only pipe it some restricted json (lists, strings and
floats) and “navigate” through the structure with the arrow keys.

Change-Id: I7c8546459ff86c766fc03723f732c7d9f863ceaa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2862
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/Profpatsch/struct-edit/default.nix

@@ -0,0 +1,13 @@
+{ depot, ... }:
+depot.nix.buildGo.program {
+    name = "struct-edit";
+    srcs = [
+      ./main.go
+    ];
+    deps = [
+      depot.third_party.gopkgs."github.com".charmbracelet.bubbletea
+      depot.third_party.gopkgs."github.com".charmbracelet.lipgloss
+      depot.third_party.gopkgs."github.com".muesli.termenv
+      depot.third_party.gopkgs."github.com".mattn.go-isatty
+    ];
+}