Ess 0.5.2

Install this if you are on 0.5.1 — the UI kit could not draw at all in that release.

Fixed

• ess_ui.gfx was missing from the shipped vz-patch.wad. Ess.UI renders every widget through one
  runtime Scaleform movie, and that movie was not in the wad 0.5.1 installed. Menus, panels, toasts, the
  board, chat, Ess.UI.Theme and Ess.UI.setScale therefore did nothing at all on a clean install — and
  did so silently, because the widget host constructs successfully whether or not the asset exists,
  so nothing errored and nothing reached the log.

  The wad had been committed once, before the UI kit was rewritten to use a runtime movie, and was never
  regenerated; build/package.py only checked that the file existed, which a stale wad passes. It did not
  reproduce in development because the dev install had the movie injected by hand.

  The 11 pre-rewrite per-widget movies were present the whole time and are unchanged. ess_ui is added
  alongside them, so the wad now carries 12 assets.

Added

• build/package.py now reads the wad's asset table instead of trusting it. check_wad() parses the
  FFCS ASET and fails the build if any movie named in Ess.UI.FILES is missing, so this cannot ship again.
  The names come from Ess.UI.FILES itself, so adding a movie to the kit extends the gate automatically.
  Verified against the 0.5.1 wad: the gate rejects it.
• docs/UI_WAD.md — how the UI wad works and how to inject a movie. Documents the trap behind this
  bug: assets are registered under their bare stem (ess_ui) but loaded with the extension
  (ess_ui.gfx), so injecting under the full filename registers a name the engine never looks up.