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/validation/enum.ts

@@ -0,0 +1,54 @@
+import type {CodeKeywordDefinition, ErrorObject, KeywordErrorDefinition} from "../../types"
+import type {KeywordCxt} from "../../compile/validate"
+import {_, or, Name, Code} from "../../compile/codegen"
+import {useFunc} from "../../compile/util"
+import equal from "../../runtime/equal"
+
+export type EnumError = ErrorObject<"enum", {allowedValues: any[]}, any[] | {$data: string}>
+
+const error: KeywordErrorDefinition = {
+  message: "must be equal to one of the allowed values",
+  params: ({schemaCode}) => _`{allowedValues: ${schemaCode}}`,
+}
+
+const def: CodeKeywordDefinition = {
+  keyword: "enum",
+  schemaType: "array",
+  $data: true,
+  error,
+  code(cxt: KeywordCxt) {
+    const {gen, data, $data, schema, schemaCode, it} = cxt
+    if (!$data && schema.length === 0) throw new Error("enum must have non-empty array")
+    const useLoop = schema.length >= it.opts.loopEnum
+    let eql: Name | undefined
+    const getEql = (): Name => (eql ??= useFunc(gen, equal))
+
+    let valid: Code
+    if (useLoop || $data) {
+      valid = gen.let("valid")
+      cxt.block$data(valid, loopEnum)
+    } else {
+      /* istanbul ignore if */
+      if (!Array.isArray(schema)) throw new Error("ajv implementation error")
+      const vSchema = gen.const("vSchema", schemaCode)
+      valid = or(...schema.map((_x: unknown, i: number) => equalCode(vSchema, i)))
+    }
+    cxt.pass(valid)
+
+    function loopEnum(): void {
+      gen.assign(valid, false)
+      gen.forOf("v", schemaCode as Code, (v) =>
+        gen.if(_`${getEql()}(${data}, ${v})`, () => gen.assign(valid, true).break())
+      )
+    }
+
+    function equalCode(vSchema: Name, i: number): Code {
+      const sch = schema[i]
+      return typeof sch === "object" && sch !== null
+        ? _`${getEql()}(${data}, ${vSchema}[${i}])`
+        : _`${data} === ${sch}`
+    }
+  },
+}
+
+export default def