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/json4lua/examples/jsonrpc.lua

@@ -0,0 +1,21 @@
+--
+-- jsonrpc.lua
+-- Installed in a CGILua webserver environment (with necessary CGI Lua 5.0 patch)
+--
+require ('json.rpcserver')
+
+-- The Lua class that is to serve JSON RPC requests
+local myServer = {
+  echo = function (msg) return msg end,
+  average = function(...)
+    local total=0
+    local count=0
+    for i=1, table.getn(arg) do
+      total = total + arg[i]
+      count = count + 1
+    end
+    return { average= total/count, sum = total, n=count }
+  end
+}
+
+json.rpcserver.serve(myServer)