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/estree-walker/package.json

@@ -0,0 +1,38 @@
+{
+	"name": "estree-walker",
+	"description": "Traverse an ESTree-compliant AST",
+	"version": "3.0.3",
+	"private": false,
+	"author": "Rich Harris",
+	"license": "MIT",
+	"repository": {
+		"type": "git",
+		"url": "https://github.com/Rich-Harris/estree-walker"
+	},
+	"type": "module",
+	"module": "./src/index.js",
+	"exports": {
+		"./package.json": "./package.json",
+		".": {
+			"types": "./types/index.d.ts",
+			"import": "./src/index.js"
+		}
+	},
+	"types": "types/index.d.ts",
+	"scripts": {
+		"prepublishOnly": "tsc && npm test",
+		"test": "uvu test"
+	},
+	"dependencies": {
+		"@types/estree": "^1.0.0"
+	},
+	"devDependencies": {
+		"typescript": "^4.9.0",
+		"uvu": "^0.5.1"
+	},
+	"files": [
+		"src",
+		"types",
+		"README.md"
+	]
+}