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/workbox-build/build/lib/replace-and-update-source-map.js

@@ -0,0 +1,98 @@
+"use strict";
+/*
+  Copyright 2019 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.replaceAndUpdateSourceMap = void 0;
+const source_map_1 = require("source-map");
+/**
+ * Adapted from https://github.com/nsams/sourcemap-aware-replace, with modern
+ * JavaScript updates, along with additional properties copied from originalMap.
+ *
+ * @param {Object} options
+ * @param {string} options.jsFilename The name for the file whose contents
+ * correspond to originalSource.
+ * @param {Object} options.originalMap The sourcemap for originalSource,
+ * prior to any replacements.
+ * @param {string} options.originalSource The source code, prior to any
+ * replacements.
+ * @param {string} options.replaceString A string to swap in for searchString.
+ * @param {string} options.searchString A string in originalSource to replace.
+ * Only the first occurrence will be replaced.
+ * @return {{source: string, map: string}} An object containing both
+ * originalSource with the replacement applied, and the modified originalMap.
+ *
+ * @private
+ */
+async function replaceAndUpdateSourceMap({ jsFilename, originalMap, originalSource, replaceString, searchString, }) {
+    const generator = new source_map_1.SourceMapGenerator({
+        file: jsFilename,
+    });
+    const consumer = await new source_map_1.SourceMapConsumer(originalMap);
+    let pos;
+    let src = originalSource;
+    const replacements = [];
+    let lineNum = 0;
+    let filePos = 0;
+    const lines = src.split('\n');
+    for (let line of lines) {
+        lineNum++;
+        let searchPos = 0;
+        while ((pos = line.indexOf(searchString, searchPos)) !== -1) {
+            src =
+                src.substring(0, filePos + pos) +
+                    replaceString +
+                    src.substring(filePos + pos + searchString.length);
+            line =
+                line.substring(0, pos) +
+                    replaceString +
+                    line.substring(pos + searchString.length);
+            replacements.push({ line: lineNum, column: pos });
+            searchPos = pos + replaceString.length;
+        }
+        filePos += line.length + 1;
+    }
+    replacements.reverse();
+    consumer.eachMapping((mapping) => {
+        for (const replacement of replacements) {
+            if (replacement.line === mapping.generatedLine &&
+                mapping.generatedColumn > replacement.column) {
+                const offset = searchString.length - replaceString.length;
+                mapping.generatedColumn -= offset;
+            }
+        }
+        if (mapping.source) {
+            const newMapping = {
+                generated: {
+                    line: mapping.generatedLine,
+                    column: mapping.generatedColumn,
+                },
+                original: {
+                    line: mapping.originalLine,
+                    column: mapping.originalColumn,
+                },
+                source: mapping.source,
+            };
+            return generator.addMapping(newMapping);
+        }
+        return mapping;
+    });
+    consumer.destroy();
+    // JSON.parse returns any.
+    // eslint-disable-next-line  @typescript-eslint/no-unsafe-assignment
+    const updatedSourceMap = Object.assign(JSON.parse(generator.toString()), {
+        names: originalMap.names,
+        sourceRoot: originalMap.sourceRoot,
+        sources: originalMap.sources,
+        sourcesContent: originalMap.sourcesContent,
+    });
+    return {
+        map: JSON.stringify(updatedSourceMap),
+        source: src,
+    };
+}
+exports.replaceAndUpdateSourceMap = replaceAndUpdateSourceMap;