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/leven/package.json

@@ -0,0 +1,57 @@
+{
+	"name": "leven",
+	"version": "3.1.0",
+	"description": "Measure the difference between two strings using the fastest JS implementation of the Levenshtein distance algorithm",
+	"license": "MIT",
+	"repository": "sindresorhus/leven",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=6"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd",
+		"bench": "matcha bench.js"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"leven",
+		"levenshtein",
+		"distance",
+		"algorithm",
+		"algo",
+		"string",
+		"difference",
+		"diff",
+		"fast",
+		"fuzzy",
+		"similar",
+		"similarity",
+		"compare",
+		"comparison",
+		"edit",
+		"text",
+		"match",
+		"matching"
+	],
+	"devDependencies": {
+		"ava": "^1.4.1",
+		"fast-levenshtein": "^2.0.6",
+		"ld": "^0.1.0",
+		"levdist": "^2.2.9",
+		"levenshtein": "^1.0.5",
+		"levenshtein-component": "^0.0.1",
+		"levenshtein-edit-distance": "^2.0.3",
+		"matcha": "^0.7.0",
+		"natural": "^0.6.3",
+		"talisman": "^0.21.0",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
+	}
+}