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/tinypool/dist/entry/process.js

@@ -0,0 +1,72 @@
+import { stderr, stdout } from "../utils-De75vAgL.js";
+import { getHandler, throwInNextTick } from "../utils-B--2TaWv.js";
+
+//#region src/entry/process.ts
+process.__tinypool_state__ = {
+	isChildProcess: true,
+	isTinypoolWorker: true,
+	workerData: null,
+	workerId: Number(process.env.TINYPOOL_WORKER_ID)
+};
+const memoryUsage = process.memoryUsage.bind(process);
+const send = process.send.bind(process);
+process.on("message", (message) => {
+	if (!message || !message.__tinypool_worker_message__) return;
+	if (message.source === "pool") {
+		const { filename, name } = message;
+		(async function() {
+			if (filename !== null) await getHandler(filename, name);
+			send({
+				ready: true,
+				source: "pool",
+				__tinypool_worker_message__: true
+			}, () => {});
+		})().catch(throwInNextTick);
+		return;
+	}
+	if (message.source === "port") {
+		onMessage(message).catch(throwInNextTick);
+		return;
+	}
+	throw new Error(`Unexpected TinypoolWorkerMessage ${JSON.stringify(message)}`);
+});
+async function onMessage(message) {
+	const { taskId, task, filename, name } = message;
+	let response;
+	try {
+		const handler = await getHandler(filename, name);
+		if (handler === null) throw new Error(`No handler function "${name}" exported from "${filename}"`);
+		const result = await handler(task);
+		response = {
+			source: "port",
+			__tinypool_worker_message__: true,
+			taskId,
+			result,
+			error: null,
+			usedMemory: memoryUsage().heapUsed
+		};
+		if (stdout()?.writableLength > 0) await new Promise((resolve) => process.stdout.write("", resolve));
+		if (stderr()?.writableLength > 0) await new Promise((resolve) => process.stderr.write("", resolve));
+	} catch (error) {
+		response = {
+			source: "port",
+			__tinypool_worker_message__: true,
+			taskId,
+			result: null,
+			error: serializeError(error),
+			usedMemory: memoryUsage().heapUsed
+		};
+	}
+	send(response);
+}
+function serializeError(error) {
+	if (error instanceof Error) return {
+		...error,
+		name: error.name,
+		stack: error.stack,
+		message: error.message
+	};
+	return String(error);
+}
+
+//#endregion