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/alts-inline.ink

@@ -0,0 +1,37 @@
+VAR counter = 0
+-> coffee
+
+= coffee
+{I bought a coffee with my five-pound note.|I bought a second coffee for my friend.|I didn't have enough money to buy any more coffee.}
+~ counter++
+{ counter < 4 : -> coffee | -> today }
+
+= today
+It was {&Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday} today.
+~ counter++
+{ counter < 15 : -> today | -> joke}
+
+= joke
+He told me a joke. {!I laughed politely.|I smiled.|I grimaced.|I promised myself to not react again.}
+~ counter++
+{ counter < 20 : -> joke | -> coin}
+
+= coin
+{ SEED_RANDOM(20 - counter) }
+I tossed the coin. {~Heads|Tails}.
+~ counter++
+{ counter < 22 : -> coin | -> lights}
+
+= lights
+I took a step forward. {!||Then the lights went out. -> dark }
+~ counter++
+{ counter < 27 : -> lights | -> ratbear}
+
+= dark
+So dark...
+-> ratbear
+
+= ratbear
+The Ratbear {&{wastes no time and |}swipes|scratches } {&at you|into your {&leg|arm|cheek}}.
+~ counter++
+{ counter < 32 : -> ratbear | -> END }