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/runtime/binding.lua

@@ -0,0 +1,42 @@
+local narrator, describe, it, assert = ...
+
+local content = [[
+  ~ beep()
+  { sum(1, 2) }
+  { did_solve_puzzle("labirint") }
+]]
+
+local book = narrator.parse_content(content)
+local story = narrator.init_story(book)
+
+local is_beeped = false
+local puzzles = { }
+
+story:bind('beep', function()
+  is_beeped = true
+end)
+
+story:bind('sum', function(x, y)
+  return x + y
+end)
+
+story:bind('did_solve_puzzle', function(puzzle)
+  puzzles[puzzle] = true
+end)
+
+story:begin()
+
+it('Was a beep?', function()
+  assert.is_true(is_beeped)
+end)
+
+it('Sum is equal to 3.', function()
+  local paragraphs = story:continue()
+  assert.equal(#paragraphs, 1)
+  assert.equal('3', paragraphs[1].text)
+end)
+
+it('Labirint is sovled.', function()
+  local puzzle_is_solved = puzzles['labirint']
+  assert.is_true(puzzle_is_solved)
+end)