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/compile/validate/boolSchema.ts

@@ -0,0 +1,47 @@
+import type {KeywordErrorDefinition, KeywordErrorCxt} from "../../types"
+import type {SchemaCxt} from ".."
+import {reportError} from "../errors"
+import {_, Name} from "../codegen"
+import N from "../names"
+
+const boolError: KeywordErrorDefinition = {
+  message: "boolean schema is false",
+}
+
+export function topBoolOrEmptySchema(it: SchemaCxt): void {
+  const {gen, schema, validateName} = it
+  if (schema === false) {
+    falseSchemaError(it, false)
+  } else if (typeof schema == "object" && schema.$async === true) {
+    gen.return(N.data)
+  } else {
+    gen.assign(_`${validateName}.errors`, null)
+    gen.return(true)
+  }
+}
+
+export function boolOrEmptySchema(it: SchemaCxt, valid: Name): void {
+  const {gen, schema} = it
+  if (schema === false) {
+    gen.var(valid, false) // TODO var
+    falseSchemaError(it)
+  } else {
+    gen.var(valid, true) // TODO var
+  }
+}
+
+function falseSchemaError(it: SchemaCxt, overrideAllErrors?: boolean): void {
+  const {gen, data} = it
+  // TODO maybe some other interface should be used for non-keyword validation errors...
+  const cxt: KeywordErrorCxt = {
+    gen,
+    keyword: "false schema",
+    data,
+    schema: false,
+    schemaCode: false,
+    schemaValue: false,
+    params: {},
+    it,
+  }
+  reportError(cxt, boolError, undefined, overrideAllErrors)
+}