feat: minimal HUD with one floating menu and objective chip

Phase 4 of turning the game into the company landing page.

- Only the menu button, a compact objective chip and the touch
  controls stay on screen; speed shows only while driving.
- The objective chip shows the next goal in one line, its distance and
  an arrow that turns towards it (replaces the compass strip); tapping
  it opens the mission list.
- One floating menu holds map, missions, status, products, real-world,
  camera, stable mode, sound, graphics, minimap, fullscreen, help,
  restart and back to the start screen. It closes on a second tap, a
  tap outside, Escape, or after an action.
- Missions, status and help open as sheets; street label, rank bar,
  status panel, toolbar and compass are gone. The minimap is optional
  and off by default.
- Share the icon set and sheet dialog between start screen and HUD.
- Layout checked for phone portrait, landscape and safe areas.

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

src/components/shared/Sheet.jsx

@@ -0,0 +1,47 @@
+import { useEffect, useRef } from 'react';
+import { Icon } from './Icon.jsx';
+
+/** @typedef {{id: string, open: boolean, title: string, closeLabel: string, onClose: function,
+ * children?: import('react').ReactNode}} SheetProps */
+/**
+ * Modal panel built on the native dialog (focus trap and Escape for free). Styled by the
+ * `.info-sheet` rules: a centred card on wide screens, a bottom sheet on phones.
+ * @param {SheetProps} props - Visibility, title, close label and callback, and content.
+ * @returns {import('react').ReactElement} Dialog element.
+ */
+export function Sheet({ id, open, title, closeLabel, onClose, children }) {
+  const dialog = useRef(null);
+
+  // Keep the native dialog in step with `open`; closing by Escape reports back through onClose.
+  useEffect(() => {
+    const element = dialog.current;
+    if (!element) return;
+    if (open && !element.open) element.showModal();
+    if (!open && element.open) element.close();
+  }, [open]);
+
+  return (
+    <dialog
+      ref={dialog}
+      id={id}
+      aria-labelledby={`${id}-title`}
+      onClose={onClose}
+      className="info-sheet"
+    >
+      <header className="mb-4 flex items-center justify-between gap-4">
+        <h2 id={`${id}-title`} className="text-lg font-bold">
+          {title}
+        </h2>
+        <button
+          type="button"
+          className="start-icon-button"
+          aria-label={closeLabel}
+          onClick={onClose}
+        >
+          <Icon name="close" className="h-5 w-5" />
+        </button>
+      </header>
+      {open && children}
+    </dialog>
+  );
+}