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/is-async-function/test/index.js

@@ -0,0 +1,91 @@
+'use strict';
+
+/* globals window */
+
+var test = require('tape');
+var isAsyncFunction = require('../index');
+var generatorFuncs = require('make-generator-function')();
+var asyncFuncs = require('make-async-function').list();
+var hasToStringTag = require('has-tostringtag/shams')();
+
+var forEach = require('for-each');
+
+test('returns false for non-functions', function (t) {
+	var nonFuncs = [
+		true,
+		false,
+		null,
+		undefined,
+		{},
+		[],
+		/a/g,
+		'string',
+		42,
+		new Date()
+	];
+	t.plan(nonFuncs.length);
+	forEach(nonFuncs, function (nonFunc) {
+		t.notOk(isAsyncFunction(nonFunc), nonFunc + ' is not a function');
+	});
+	t.end();
+});
+
+test('returns false for non-async functions', function (t) {
+	var func = function () {};
+	t.notOk(isAsyncFunction(func), 'anonymous function is not an async function');
+
+	var namedFunc = function foo() {};
+	t.notOk(isAsyncFunction(namedFunc), 'named function is not an async function');
+
+	if (typeof window === 'undefined') {
+		t.skip('window.alert is not an async function');
+	} else {
+		t.notOk(isAsyncFunction(window.alert), 'window.alert is not an async function');
+	}
+	t.end();
+});
+
+var fakeToString = function () { return 'async function () { return "TOTALLY REAL I SWEAR!"; }'; };
+
+test('returns false for non-async function with faked toString', function (t) {
+	var func = function () {};
+	func.toString = fakeToString;
+
+	t.notEqual(String(func), Function.prototype.toString.apply(func), 'faked toString is not real toString');
+	t.notOk(isAsyncFunction(func), 'anonymous function with faked toString is not an async function');
+	t.end();
+});
+
+test('returns false for generator functions', function (t) {
+	if (generatorFuncs.length > 0) {
+		forEach(generatorFuncs, function (generatorFunc) {
+			t.notOk(isAsyncFunction(generatorFunc), generatorFunc + ' is not async function');
+		});
+	} else {
+		t.skip('generator function is not async function - this environment does not support ES6 generator functions. Please use an engine that supports them.');
+	}
+	t.end();
+});
+
+test('returns false for non-async function with faked @@toStringTag', { skip: !hasToStringTag || asyncFuncs.length === 0 }, function (t) {
+	var asyncFunc = asyncFuncs[0];
+	/** @type {{ toString(): unknown; valueOf(): unknown; [Symbol.toStringTag]?: unknown }} */
+	var fakeAsyncFunction = {
+		toString: function () { return String(asyncFunc); },
+		valueOf: function () { return asyncFunc; }
+	};
+	fakeAsyncFunction[Symbol.toStringTag] = 'AsyncFunction';
+	t.notOk(isAsyncFunction(fakeAsyncFunction), 'fake AsyncFunction with @@toStringTag "AsyncFunction" is not an async function');
+	t.end();
+});
+
+test('returns true for async functions', function (t) {
+	if (asyncFuncs.length > 0) {
+		forEach(asyncFuncs, function (asyncFunc) {
+			t.ok(isAsyncFunction(asyncFunc), asyncFunc + ' is async function');
+		});
+	} else {
+		t.skip('async function is async function - this environment does not support ES2018 async functions. Please use an engine that supports them.');
+	}
+	t.end();
+});