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/labels-choices.ink

@@ -0,0 +1,32 @@
+-> meet_guard
+
+=== meet_guard ===
+The guard frowns at you.
+
+* 	(greet) [Greet him]
+	'Greetings.'
+*	(get_out) 'Get out of my way[.'],' you tell the guard.
+
+- 	'Hmm,' replies the guard.
+
+*	{greet} 	'Having a nice day?' // only if you greeted him
+
+* 	'Hmm?'[] you reply.
+
+*	{get_out} [Shove him aside] 	 // only if you threatened him
+	You shove him sharply. He stares in reply, and draws his sword!
+	-> fight_guard 			// this route diverts out of the weave
+
+-	'Mff,' the guard replies, and then offers you a paper bag. 'Toffee?'
+
+
+=== fight_guard ===
+
+-> throw_something
+
+= throw_something
+*	(rock) [Throw rock at guard] -> throw
+* 	(sand) [Throw sand at guard] -> throw
+
+= throw
+You hurl {throw_something.rock:a rock|a handful of sand} at the guard.