fix(sp): revert dungeon to legacy renderer + fix splash (working game restored)

The render-kit SP dungeon shipped without a player-centered camera or entity sprites,
so it drew the whole level tiny in a corner with a red-dot monster. Disable it and fall
back to the proven legacy renderer (original tiles, real monster, centered view) until
the kit has a camera + sprites. RK.SPGame/spRenderPicker kept but dormant (one flag to
re-enable). Splash legend: draw every icon (incl. the player) as a uniform grid tile —
no avatar overlay — so the four rows align AND the player shows the original hero tile.

html/js/ui/spRenderPicker.js

@@ -30,8 +30,13 @@
         doc().head.appendChild(s);
     }
 
+    // Disabled until the single-player render-kit path (RK.SPGame) has a camera + entity sprites.
+    // Keeping the module wired so re-enabling is a one-line flip.
+    var ENABLED = false;
+
     function build() {
         var h = host();
+        if (!ENABLED) { if (h) h.classList.add('hidden'); return; }
         if (!h || !RK.RENDER_MODES || !RK.SPGame) return;
         ensureStyle();
         h.innerHTML = '';