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/dist/2020.d.ts

@@ -0,0 +1,19 @@
+import type { AnySchemaObject } from "./types";
+import AjvCore, { Options } from "./core";
+export declare class Ajv2020 extends AjvCore {
+    constructor(opts?: Options);
+    _addVocabularies(): void;
+    _addDefaultMetaSchema(): void;
+    defaultMeta(): string | AnySchemaObject | undefined;
+}
+export default Ajv2020;
+export { Format, FormatDefinition, AsyncFormatDefinition, KeywordDefinition, KeywordErrorDefinition, CodeKeywordDefinition, MacroKeywordDefinition, FuncKeywordDefinition, Vocabulary, Schema, SchemaObject, AnySchemaObject, AsyncSchema, AnySchema, ValidateFunction, AsyncValidateFunction, ErrorObject, ErrorNoParams, } from "./types";
+export { Plugin, Options, CodeOptions, InstanceOptions, Logger, ErrorsTextOptions } from "./core";
+export { SchemaCxt, SchemaObjCxt } from "./compile";
+export { KeywordCxt } from "./compile/validate";
+export { DefinedError } from "./vocabularies/errors";
+export { JSONType } from "./compile/rules";
+export { JSONSchemaType } from "./types/json-schema";
+export { _, str, stringify, nil, Name, Code, CodeGen, CodeGenOptions } from "./compile/codegen";
+export { default as ValidationError } from "./runtime/validation_error";
+export { default as MissingRefError } from "./compile/ref_error";