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/unicode-property-aliases-ecmascript/index.js

@@ -0,0 +1,57 @@
+// Generated using `npm run build`. Do not edit!
+module.exports = new Map([
+	['scx', 'Script_Extensions'],
+	['sc', 'Script'],
+	['gc', 'General_Category'],
+	['AHex', 'ASCII_Hex_Digit'],
+	['Alpha', 'Alphabetic'],
+	['Bidi_C', 'Bidi_Control'],
+	['Bidi_M', 'Bidi_Mirrored'],
+	['Cased', 'Cased'],
+	['CI', 'Case_Ignorable'],
+	['CWCF', 'Changes_When_Casefolded'],
+	['CWCM', 'Changes_When_Casemapped'],
+	['CWKCF', 'Changes_When_NFKC_Casefolded'],
+	['CWL', 'Changes_When_Lowercased'],
+	['CWT', 'Changes_When_Titlecased'],
+	['CWU', 'Changes_When_Uppercased'],
+	['Dash', 'Dash'],
+	['Dep', 'Deprecated'],
+	['DI', 'Default_Ignorable_Code_Point'],
+	['Dia', 'Diacritic'],
+	['EBase', 'Emoji_Modifier_Base'],
+	['EComp', 'Emoji_Component'],
+	['EMod', 'Emoji_Modifier'],
+	['Emoji', 'Emoji'],
+	['EPres', 'Emoji_Presentation'],
+	['Ext', 'Extender'],
+	['ExtPict', 'Extended_Pictographic'],
+	['Gr_Base', 'Grapheme_Base'],
+	['Gr_Ext', 'Grapheme_Extend'],
+	['Hex', 'Hex_Digit'],
+	['IDC', 'ID_Continue'],
+	['Ideo', 'Ideographic'],
+	['IDS', 'ID_Start'],
+	['IDSB', 'IDS_Binary_Operator'],
+	['IDST', 'IDS_Trinary_Operator'],
+	['Join_C', 'Join_Control'],
+	['LOE', 'Logical_Order_Exception'],
+	['Lower', 'Lowercase'],
+	['Math', 'Math'],
+	['NChar', 'Noncharacter_Code_Point'],
+	['Pat_Syn', 'Pattern_Syntax'],
+	['Pat_WS', 'Pattern_White_Space'],
+	['QMark', 'Quotation_Mark'],
+	['Radical', 'Radical'],
+	['RI', 'Regional_Indicator'],
+	['SD', 'Soft_Dotted'],
+	['STerm', 'Sentence_Terminal'],
+	['Term', 'Terminal_Punctuation'],
+	['UIdeo', 'Unified_Ideograph'],
+	['Upper', 'Uppercase'],
+	['VS', 'Variation_Selector'],
+	['WSpace', 'White_Space'],
+	['space', 'White_Space'],
+	['XIDC', 'XID_Continue'],
+	['XIDS', 'XID_Start']
+]);