Add progressive web app companion for cross-platform access

Vite + TypeScript PWA that mirrors the Android app's core features:
- Pre-processed shelter data (build-time UTM33N→WGS84 conversion)
- Leaflet map with shelter markers, user location, and offline tiles
- Canvas compass arrow (ported from DirectionArrowView.kt)
- IndexedDB shelter cache with 7-day staleness check
- Service worker with CacheFirst tiles and precached app shell
- i18n for en, nb, nn (ported from Android strings.xml)
- iOS/Android compass handling with low-pass filter
- Respects user map interaction (no auto-snap on pan/zoom)
- Build revision cache-breaker for reliable SW updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pwa/node_modules/es-abstract/2018/ObjectCreate.js

@@ -0,0 +1,50 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $ObjectCreate = GetIntrinsic('%Object.create%', true);
+var $TypeError = require('es-errors/type');
+var $SyntaxError = require('es-errors/syntax');
+var isObject = require('es-object-atoms/isObject');
+
+var IsArray = require('./IsArray');
+
+var forEach = require('../helpers/forEach');
+
+var SLOT = require('internal-slot');
+
+var hasProto = require('has-proto')();
+
+// https://262.ecma-international.org/6.0/#sec-objectcreate
+
+module.exports = function ObjectCreate(proto, internalSlotsList) {
+	if (proto !== null && !isObject(proto)) {
+		throw new $TypeError('Assertion failed: `proto` must be null or an object');
+	}
+	var slots = arguments.length < 2 ? [] : internalSlotsList; // step 1
+	if (arguments.length >= 2 && !IsArray(slots)) {
+		throw new $TypeError('Assertion failed: `internalSlotsList` must be an Array');
+	}
+
+	var O;
+	if (hasProto) {
+		O = { __proto__: proto };
+	} else if ($ObjectCreate) {
+		O = $ObjectCreate(proto);
+	} else {
+		if (proto === null) {
+			throw new $SyntaxError('native Object.create support is required to create null objects');
+		}
+		var T = function T() {};
+		T.prototype = proto;
+		O = new T();
+	}
+
+	if (slots.length > 0) {
+		forEach(slots, function (slot) {
+			SLOT.set(O, slot, void undefined);
+		});
+	}
+
+	return O; // step 6
+};