Vendor libs/hump, sfxrlua, json4lua, narrator as real files

These were committed as empty submodule gitlinks with no .gitmodules,
so the folders were never populated and the game could not load
(require of libs/hump/timer, libs/sfxrlua/sfxr, narrator.narrator).
Checked out each at its pinned commit and vendored the files, matching
the existing bundled-libs convention. Removed the junk libs/libs/ tree.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

libs/narrator/test/units/choices-fallback.ink

@@ -0,0 +1,10 @@
+-> find_help
+
+=== find_help ===
+
+	You search desperately for a friendly face in the crowd.
+	*	The woman in the hat[?] pushes you roughly aside. -> find_help
+	*	The man with the briefcase[?] looks disgusted as you stumble past him. -> find_help
+	*	->
+		But it is too late: you collapse onto the station platform. This is the end.
+		-> END