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/2024/StringPad.js

@@ -0,0 +1,43 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+var callBound = require('call-bound');
+var isInteger = require('math-intrinsics/isInteger');
+
+var $strSlice = callBound('String.prototype.slice');
+
+// https://262.ecma-international.org/15.0/#sec-stringpad
+
+module.exports = function StringPad(S, maxLength, fillString, placement) {
+	if (typeof S !== 'string') {
+		throw new $TypeError('Assertion failed: `S` must be a String');
+	}
+	if (!isInteger(maxLength) || maxLength < 0) {
+		throw new $TypeError('Assertion failed: `maxLength` must be a non-negative integer');
+	}
+	if (typeof fillString !== 'string') {
+		throw new $TypeError('Assertion failed: `fillString` must be a String');
+	}
+	if (placement !== 'start' && placement !== 'end' && placement !== 'START' && placement !== 'END') {
+		throw new $TypeError('Assertion failed: `placement` must be ~START~ or ~END~');
+	}
+
+	var stringLength = S.length; // step 1
+
+	if (maxLength <= stringLength) { return S; } // step 2
+
+	if (fillString === '') { return S; } // step 3
+
+	var fillLen = maxLength - stringLength; // step 4
+
+	// 5. Let _truncatedStringFiller_ be the String value consisting of repeated concatenations of _fillString_ truncated to length _fillLen_.
+	var truncatedStringFiller = '';
+	while (truncatedStringFiller.length < fillLen) {
+		truncatedStringFiller += fillString;
+	}
+	truncatedStringFiller = $strSlice(truncatedStringFiller, 0, fillLen);
+
+	if (placement === 'start' || placement === 'START') { return truncatedStringFiller + S; } // step 6
+
+	return S + truncatedStringFiller; // step 7
+};