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/terser/lib/sourcemap.js

@@ -0,0 +1,148 @@
+/***********************************************************************
+
+  A JavaScript tokenizer / parser / beautifier / compressor.
+  https://github.com/mishoo/UglifyJS2
+
+  -------------------------------- (C) ---------------------------------
+
+                           Author: Mihai Bazon
+                         <mihai.bazon@gmail.com>
+                       http://mihai.bazon.net/blog
+
+  Distributed under the BSD license:
+
+    Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com>
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+        * Redistributions of source code must retain the above
+          copyright notice, this list of conditions and the following
+          disclaimer.
+
+        * Redistributions in binary form must reproduce the above
+          copyright notice, this list of conditions and the following
+          disclaimer in the documentation and/or other materials
+          provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
+    EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+    PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
+    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+ ***********************************************************************/
+
+"use strict";
+
+import {SourceMapConsumer, SourceMapGenerator} from "@jridgewell/source-map";
+import {defaults, HOP} from "./utils/index.js";
+
+// a small wrapper around source-map and @jridgewell/source-map
+function* SourceMap(options) {
+    options = defaults(options, {
+        file : null,
+        root : null,
+        orig : null,
+        files: {},
+    });
+
+    var orig_map;
+    var generator = new SourceMapGenerator({
+        file       : options.file,
+        sourceRoot : options.root
+    });
+
+    let sourcesContent = {__proto__: null};
+    let files = options.files;
+    for (var name in files) if (HOP(files, name)) {
+        sourcesContent[name] = files[name];
+    }
+    if (options.orig) {
+        // We support both @jridgewell/source-map (which has a sync
+        // SourceMapConsumer) and source-map (which has an async
+        // SourceMapConsumer).
+        orig_map = yield new SourceMapConsumer(options.orig);
+        if (orig_map.sourcesContent) {
+            orig_map.sources.forEach(function(source, i) {
+                var content = orig_map.sourcesContent[i];
+                if (content) {
+                    sourcesContent[source] = content;
+                }
+            });
+        }
+    }
+
+    function add(source, gen_line, gen_col, orig_line, orig_col, name) {
+        let generatedPos = { line: gen_line, column: gen_col };
+
+        if (orig_map) {
+            var info = orig_map.originalPositionFor({
+                line: orig_line,
+                column: orig_col
+            });
+            if (info.source === null) {
+                generator.addMapping({
+                    generated: generatedPos,
+                    original: null,
+                    source: null,
+                    name: null
+                });
+                return;
+            }
+            source = info.source;
+            orig_line = info.line;
+            orig_col = info.column;
+            name = info.name || name;
+        }
+        generator.addMapping({
+            generated : generatedPos,
+            original  : { line: orig_line, column: orig_col },
+            source    : source,
+            name      : name
+        });
+        generator.setSourceContent(source, sourcesContent[source]);
+    }
+
+    function clean(map) {
+        const allNull = map.sourcesContent && map.sourcesContent.every(c => c == null);
+        if (allNull) delete map.sourcesContent;
+        if (map.file === undefined) delete map.file;
+        if (map.sourceRoot === undefined) delete map.sourceRoot;
+        return map;
+    }
+
+    function getDecoded() {
+        if (!generator.toDecodedMap) return null;
+        return clean(generator.toDecodedMap());
+    }
+
+    function getEncoded() {
+        return clean(generator.toJSON());
+    }
+
+    function destroy() {
+        // @jridgewell/source-map's SourceMapConsumer does not need to be
+        // manually freed.
+        if (orig_map && orig_map.destroy) orig_map.destroy();
+    }
+
+    return {
+        add,
+        getDecoded,
+        getEncoded,
+        destroy,
+    };
+}
+
+export {
+    SourceMap,
+};