Fix Gen 1/2 battle, menu, PC and audio parity gaps; wire luacheck into CI

CLOSES #1484, CLOSES #1486, CLOSES #1513, CLOSES #1517, CLOSES #1556, CLOSES #1564, CLOSES #1567

tests/drivers/errorhandler_probe_bug1517_test.lua

@@ -0,0 +1,46 @@
+-- Driver: #1517's other half, the error handler that hid the crash.
+--
+-- boot.lua's deferErrhand picks `love.errorhandler or love.errhand`, so a
+-- love.errorhandler that returns nil ends love.run's `while func do` loop and
+-- the process leaves to the OS with no error screen and nothing on stdout.
+-- LOVE 11.5 pre-populates love.errhand only, so main.lua capturing
+-- love.errorhandler captured nil and every Lua error in every shipped build
+-- exited silently.  Measured on the installed 11.5:
+--   love.errorhandler type: nil / love.errhand type: function
+--
+-- Nothing here can be a unit test: the deliverable is whether a human sees
+-- LOVE's blue error screen or an app that vanishes.
+--
+--   POKEPORT_TOUCH=0 \
+--     POKEPORT_DRIVER=tests/drivers/errorhandler_probe_bug1517_test.lua love .
+--
+-- Pre-fix: the window closes on the first drawn frame after the probe arms,
+-- exit 1, no output.  Post-fix: the blue screen reads "bug1517: error-handler
+-- probe" plus the lua-error.log hint, and stays up until it is dismissed.
+return function(game)
+  local U = dofile("tests/drivers/util.lua")
+
+  U.log("[1517] love.errorhandler at boot was: "
+          .. (rawget(love, "errorhandler") and "a function" or "nil"))
+  U.log("[1517] love.errhand is: " .. type(rawget(love, "errhand")))
+
+  U.wait(30)
+
+  -- Raise from a draw callback, not from this coroutine: main.lua resumes the
+  -- driver under coroutine.resume and prints its errors itself, which is the
+  -- one path that does NOT reach love.errorhandler.  StateStack:draw only
+  -- calls the states it is actually holding, so the probe goes on the live
+  -- top state rather than on game.overworld, which is not on the stack while
+  -- the title screen or the load menu is up.
+  local target = game.stack:top()
+  U.log("[1517] arming the probe on " .. tostring(target and target.screenId))
+  local realDraw = target.draw
+  target.draw = function(self, ...)
+    if realDraw then realDraw(self, ...) end
+    error("bug1517: error-handler probe")
+  end
+
+  U.log("[1517] armed; the next drawn frame raises from love.draw")
+  U.log("[1517] you should now see LOVE's blue error screen, not a closed app")
+  while true do coroutine.yield() end
+end