Start at the factory, add PWA install and GPS real-world mode

The game now begins inside the Negin Sazan Pishgam Radmehr Atousa
vending-machine factory on the Mashhad–Chenaran road, and the world
extends ~20 km along the real driving route to Park Mellat and
Ferdowsi University.

- Factory compound: production hall with assembly line, office, yard,
  gate and company signs; first mission at its half-price demo machine
- Map data merged from four OSM extracts (factory zone, route corridor,
  region main roads, city zone), clipped to a 15 x 18 km region
- City meshes chunked and culled by distance; traffic recycled around
  the player; minimap and city map drawn from cached tiles + overview
- The Robot Market robot no longer walks with the family: it comes out
  of a machine when they arrive, greets them with expression portraits
  and goes back inside when they leave
- PWA: manifest, icons from the robot avatar, offline service worker
  generated at build time, install button / iOS steps, update prompt;
  Vazirmatn font bundled instead of Google Fonts
- Real-world mode: safety notice, GPS + compass tracking with accuracy
  smoothing, 20-40 m arrival radius, speed lock and in-person bonus

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

src/realworld.js

@@ -0,0 +1,60 @@
+import {toLocal} from './geo.js';
+
+// Real-world mode: the family follows the phone's GPS position. Phone GPS in a city is off by
+// 5–20 m and jumps around, so fixes are blended by their accuracy and arrival uses a wide radius.
+
+export const MAX_WALKING_SPEED = 6; // m/s (~22 km/h); faster means a vehicle, so buying pauses.
+
+// Blends a new fix into the previous estimate, trusting whichever is more accurate.
+export function smoothFix(previous, fix) {
+    if (!previous || fix.time - previous.time > 30000) return {...fix};
+    const weight = previous.accuracy ** 2 / (previous.accuracy ** 2 + fix.accuracy ** 2);
+    const dt = Math.max(.001, (fix.time - previous.time) / 1000);
+    const x = previous.x + (fix.x - previous.x) * weight, z = previous.z + (fix.z - previous.z) * weight;
+    // The blended estimate is a little better than either input, but never better than 3 m.
+    const accuracy = Math.max(3, Math.sqrt(1 / (1 / previous.accuracy ** 2 + 1 / fix.accuracy ** 2)) + Math.hypot(x - previous.x, z - previous.z) * .2);
+    return {x, z, accuracy, time: fix.time, speed: fix.speed ?? Math.hypot(x - previous.x, z - previous.z) / dt};
+}
+
+// How close counts as "at the machine": never tighter than 20 m, wider when GPS is poor.
+export const arrivalRadius = accuracy => Math.min(40, Math.max(20, accuracy * 1.5));
+
+export const insideWorld = (bounds, x, z) => x > bounds.minX && x < bounds.maxX && z > bounds.minZ && z < bounds.maxZ;
+
+// Watches the phone's position and compass. Calls onFix({x, z, accuracy, speed, lat, lon}),
+// onHeading(radians in the game's heading convention) and onError(message).
+export function startTracking({onFix, onHeading, onError}) {
+    if (!('geolocation' in navigator)) {
+        onError('این دستگاه موقعیت‌یابی (GPS) ندارد.');
+        return () => {};
+    }
+    let estimate = null;
+    const watch = navigator.geolocation.watchPosition(position => {
+        const {latitude: lat, longitude: lon, accuracy, speed} = position.coords, local = toLocal(lat, lon);
+        estimate = smoothFix(estimate, {...local, accuracy: Math.max(3, accuracy), speed: Number.isFinite(speed) ? speed : null, time: position.timestamp});
+        onFix({...estimate, lat, lon});
+    }, error => onError(error.code === error.PERMISSION_DENIED ? 'اجازهٔ دسترسی به موقعیت داده نشد. از تنظیمات مرورگر اجازه بدهید.' : 'موقعیت پیدا نشد؛ به فضای باز بروید.'), {
+        enableHighAccuracy: true, maximumAge: 2000, timeout: 20000
+    });
+    // Compass: iOS reports webkitCompassHeading; Android reports absolute alpha (counter-clockwise).
+    const orientation = event => {
+        const compass = event.webkitCompassHeading ?? (event.absolute && event.alpha != null ? 360 - event.alpha : null);
+        // Game heading 0 faces east and grows counter-clockwise, compass 0 faces north and grows clockwise.
+        if (compass != null) onHeading(Math.PI / 2 - compass * Math.PI / 180);
+    };
+    const eventName = 'ondeviceorientationabsolute' in window ? 'deviceorientationabsolute' : 'deviceorientation';
+    window.addEventListener(eventName, orientation);
+    return () => {
+        navigator.geolocation.clearWatch(watch);
+        window.removeEventListener(eventName, orientation);
+    };
+}
+
+// iOS needs an explicit permission prompt for the compass, and it must come from a tap.
+export async function requestCompass() {
+    try {
+        if (typeof DeviceOrientationEvent !== 'undefined' && DeviceOrientationEvent.requestPermission) await DeviceOrientationEvent.requestPermission();
+    } catch {
+        // Without the compass the family faces the direction of travel instead.
+    }
+}