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/escalade/package.json

@@ -0,0 +1,74 @@
+{
+  "name": "escalade",
+  "version": "3.2.0",
+  "repository": "lukeed/escalade",
+  "description": "A tiny (183B to 210B) and fast utility to ascend parent directories",
+  "module": "dist/index.mjs",
+  "main": "dist/index.js",
+  "types": "index.d.ts",
+  "license": "MIT",
+  "author": {
+    "name": "Luke Edwards",
+    "email": "luke.edwards05@gmail.com",
+    "url": "https://lukeed.com"
+  },
+  "exports": {
+    ".": [
+      {
+        "import": {
+          "types": "./index.d.mts",
+          "default": "./dist/index.mjs"
+        },
+        "require": {
+          "types": "./index.d.ts",
+          "default": "./dist/index.js"
+        }
+      },
+      "./dist/index.js"
+    ],
+    "./sync": [
+      {
+        "import": {
+          "types": "./sync/index.d.mts",
+          "default": "./sync/index.mjs"
+        },
+        "require": {
+          "types": "./sync/index.d.ts",
+          "default": "./sync/index.js"
+        }
+      },
+      "./sync/index.js"
+    ]
+  },
+  "files": [
+    "*.d.mts",
+    "*.d.ts",
+    "dist",
+    "sync"
+  ],
+  "modes": {
+    "sync": "src/sync.js",
+    "default": "src/async.js"
+  },
+  "engines": {
+    "node": ">=6"
+  },
+  "scripts": {
+    "build": "bundt",
+    "pretest": "npm run build",
+    "test": "uvu -r esm test -i fixtures"
+  },
+  "keywords": [
+    "find",
+    "parent",
+    "parents",
+    "directory",
+    "search",
+    "walk"
+  ],
+  "devDependencies": {
+    "bundt": "1.1.1",
+    "esm": "3.2.25",
+    "uvu": "0.3.3"
+  }
+}