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/applicator/additionalItems.ts

@@ -0,0 +1,56 @@
+import type {
+  CodeKeywordDefinition,
+  ErrorObject,
+  KeywordErrorDefinition,
+  AnySchema,
+} from "../../types"
+import type {KeywordCxt} from "../../compile/validate"
+import {_, str, not, Name} from "../../compile/codegen"
+import {alwaysValidSchema, checkStrictMode, Type} from "../../compile/util"
+
+export type AdditionalItemsError = ErrorObject<"additionalItems", {limit: number}, AnySchema>
+
+const error: KeywordErrorDefinition = {
+  message: ({params: {len}}) => str`must NOT have more than ${len} items`,
+  params: ({params: {len}}) => _`{limit: ${len}}`,
+}
+
+const def: CodeKeywordDefinition = {
+  keyword: "additionalItems" as const,
+  type: "array",
+  schemaType: ["boolean", "object"],
+  before: "uniqueItems",
+  error,
+  code(cxt: KeywordCxt) {
+    const {parentSchema, it} = cxt
+    const {items} = parentSchema
+    if (!Array.isArray(items)) {
+      checkStrictMode(it, '"additionalItems" is ignored when "items" is not an array of schemas')
+      return
+    }
+    validateAdditionalItems(cxt, items)
+  },
+}
+
+export function validateAdditionalItems(cxt: KeywordCxt, items: AnySchema[]): void {
+  const {gen, schema, data, keyword, it} = cxt
+  it.items = true
+  const len = gen.const("len", _`${data}.length`)
+  if (schema === false) {
+    cxt.setParams({len: items.length})
+    cxt.pass(_`${len} <= ${items.length}`)
+  } else if (typeof schema == "object" && !alwaysValidSchema(it, schema)) {
+    const valid = gen.var("valid", _`${len} <= ${items.length}`) // TODO var
+    gen.if(not(valid), () => validateItems(valid))
+    cxt.ok(valid)
+  }
+
+  function validateItems(valid: Name): void {
+    gen.forRange("i", items.length, len, (i) => {
+      cxt.subschema({keyword, dataProp: i, dataPropType: Type.Num}, valid)
+      if (!it.allErrors) gen.if(not(valid), () => gen.break())
+    })
+  }
+}
+
+export default def