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/json-schema-traverse/README.md

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+# json-schema-traverse
+Traverse JSON Schema passing each schema object to callback
+
+[![build](https://github.com/epoberezkin/json-schema-traverse/workflows/build/badge.svg)](https://github.com/epoberezkin/json-schema-traverse/actions?query=workflow%3Abuild)
+[![npm](https://img.shields.io/npm/v/json-schema-traverse)](https://www.npmjs.com/package/json-schema-traverse)
+[![coverage](https://coveralls.io/repos/github/epoberezkin/json-schema-traverse/badge.svg?branch=master)](https://coveralls.io/github/epoberezkin/json-schema-traverse?branch=master)
+
+
+## Install
+
+```
+npm install json-schema-traverse
+```
+
+
+## Usage
+
+```javascript
+const traverse = require('json-schema-traverse');
+const schema = {
+  properties: {
+    foo: {type: 'string'},
+    bar: {type: 'integer'}
+  }
+};
+
+traverse(schema, {cb});
+// cb is called 3 times with:
+// 1. root schema
+// 2. {type: 'string'}
+// 3. {type: 'integer'}
+
+// Or:
+
+traverse(schema, {cb: {pre, post}});
+// pre is called 3 times with:
+// 1. root schema
+// 2. {type: 'string'}
+// 3. {type: 'integer'}
+//
+// post is called 3 times with:
+// 1. {type: 'string'}
+// 2. {type: 'integer'}
+// 3. root schema
+
+```
+
+Callback function `cb` is called for each schema object (not including draft-06 boolean schemas), including the root schema, in pre-order traversal. Schema references ($ref) are not resolved, they are passed as is.  Alternatively, you can pass a `{pre, post}` object as `cb`, and then `pre` will be called before traversing child elements, and `post` will be called after all child elements have been traversed.
+
+Callback is passed these parameters:
+
+- _schema_: the current schema object
+- _JSON pointer_: from the root schema to the current schema object
+- _root schema_: the schema passed to `traverse` object
+- _parent JSON pointer_: from the root schema to the parent schema object (see below)
+- _parent keyword_: the keyword inside which this schema appears (e.g. `properties`, `anyOf`, etc.)
+- _parent schema_: not necessarily parent object/array; in the example above the parent schema for `{type: 'string'}` is the root schema
+- _index/property_: index or property name in the array/object containing multiple schemas; in the example above for `{type: 'string'}` the property name is `'foo'`
+
+
+## Traverse objects in all unknown keywords
+
+```javascript
+const traverse = require('json-schema-traverse');
+const schema = {
+  mySchema: {
+    minimum: 1,
+    maximum: 2
+  }
+};
+
+traverse(schema, {allKeys: true, cb});
+// cb is called 2 times with:
+// 1. root schema
+// 2. mySchema
+```
+
+Without option `allKeys: true` callback will be called only with root schema.
+
+
+## Enterprise support
+
+json-schema-traverse package is a part of [Tidelift enterprise subscription](https://tidelift.com/subscription/pkg/npm-json-schema-traverse?utm_source=npm-json-schema-traverse&utm_medium=referral&utm_campaign=enterprise&utm_term=repo) - it provides a centralised commercial support to open-source software users, in addition to the support provided by software maintainers.
+
+
+## Security contact
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure. Please do NOT report security vulnerability via GitHub issues.
+
+
+## License
+
+[MIT](https://github.com/epoberezkin/json-schema-traverse/blob/master/LICENSE)