feat: mousearea, datetime dates, dir(), renpy.image_size and style.rebuild for Ren'Py games

Screens get an invisible mousearea that reports the pointer entering and leaving without taking
clicks. datetime.date/datetime/timedelta support construction and date arithmetic. dir() lists the
game's variables, renpy.style.rebuild() is a no-op, and renpy.image_size answers only for pictures
the browser already holds (otherwise an IOError the game can catch).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

frontend/src/player/screens.ts

@@ -534,6 +534,7 @@ export class ScreenManager {
       case "label": return this.text(node, ctx, ["text", "label_text"], this.ev(node.args[0]), "pg-slabel");
       case "add": return this.add(node, ctx);
       case "null": return this.nullWidget(node, ctx);
+      case "mousearea": return this.mouseArea(node, ctx);
       case "bar":
       case "vbar": return this.bar(node, ctx);
     }
@@ -686,6 +687,26 @@ export class ScreenManager {
     return el;
   }
 
+  /** An invisible area that reports the pointer entering and leaving it, without taking clicks from what lies below. */
+  private mouseArea(node: any, ctx: Ctx): HTMLElement {
+    const el = document.createElement("div");
+    const props = this.resolve(node, ctx, []);
+    el.className = "pg-sw pg-snull";
+    el.style.pointerEvents = "none";
+    this.layout(el, props, ctx, { fill: false });
+    let inside = false;
+    const track = (ev: MouseEvent) => {
+      if (!el.isConnected) { document.removeEventListener("mousemove", track); return; }
+      const box = el.getBoundingClientRect();
+      const now = ev.clientX >= box.left && ev.clientX < box.right && ev.clientY >= box.top && ev.clientY < box.bottom;
+      if (now === inside) return;
+      inside = now;
+      this.run(this.ev(now ? props.hovered : props.unhovered), ctx.inst);
+    };
+    document.addEventListener("mousemove", track);
+    return el;
+  }
+
   private add(node: any, ctx: Ctx): HTMLElement | null {
     const value = this.ev(node.args[0]);
     if (value === null || value === undefined) return null;