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/ajv/lib/vocabularies/dynamic/dynamicAnchor.ts

@@ -0,0 +1,31 @@
+import type {CodeKeywordDefinition} from "../../types"
+import type {KeywordCxt} from "../../compile/validate"
+import {_, getProperty, Code} from "../../compile/codegen"
+import N from "../../compile/names"
+import {SchemaEnv, compileSchema} from "../../compile"
+import {getValidate} from "../core/ref"
+
+const def: CodeKeywordDefinition = {
+  keyword: "$dynamicAnchor",
+  schemaType: "string",
+  code: (cxt) => dynamicAnchor(cxt, cxt.schema),
+}
+
+export function dynamicAnchor(cxt: KeywordCxt, anchor: string): void {
+  const {gen, it} = cxt
+  it.schemaEnv.root.dynamicAnchors[anchor] = true
+  const v = _`${N.dynamicAnchors}${getProperty(anchor)}`
+  const validate = it.errSchemaPath === "#" ? it.validateName : _getValidate(cxt)
+  gen.if(_`!${v}`, () => gen.assign(v, validate))
+}
+
+function _getValidate(cxt: KeywordCxt): Code {
+  const {schemaEnv, schema, self} = cxt.it
+  const {root, baseId, localRefs, meta} = schemaEnv.root
+  const {schemaId} = self.opts
+  const sch = new SchemaEnv({schema, schemaId, root, baseId, localRefs, meta})
+  compileSchema.call(self, sch)
+  return getValidate(cxt, sch)
+}
+
+export default def