docs: update README

Author: MikeSpa

README.md

@@ -48,6 +48,7 @@ import { formatCHF, slugify, clamp } from '@mikespa/kit';
 | `formatDate(input)` | Date as DD.MM.YYYY | "19.06.2026" |
 | `formatTime(input)` | Time (24h) | "15:30" |
 | `formatDateTime(input)` | Date + time (locale-formatted) | "19 juin 2026, 15:30" |
+| `formatDateRange(start, end)` | Compact date range (locale-formatted) | "01.06.2026 – 15.06.2026" |
 | `formatRelative(input)` | Relative to now (locale-formatted) | "il y a 3 heures" |
 | `isToday(input)` | Whether date is today | `true` |
 | `isPast(input)` | Whether date is in the past | `true` |
@@ -59,10 +60,22 @@ import { formatCHF, slugify, clamp } from '@mikespa/kit';
 | `formatCHF(amount)` | Swiss CHF, apostrophe sep. | "1'234.50 CHF" |
 | `formatCurrency(value)` | Intl currency (CHF default) | "1 234.50 CHF" |
 | `formatCompact(value)` | Compact notation | "1,2 k" |
+| `parseCHF(input)` | Parse Swiss amount → number | `1234.5` |
 | `formatPercent(value)` | Percentage | "45,6%" |
 | `formatBytes(bytes)` | Human-readable file size | "1.5 KB" |
 | `formatPhone(input)` | Swiss phone number | "+41 79 123 45 67" |
+| `isValidPhone(input)` | Validate Swiss phone number shape | `true` |
 | `formatIBAN(input)` | IBAN with spaces | "CH56 0483 5012 3456 7800 9" |
+| `isValidIBAN(input)` | Validate IBAN check digits (any country) | `true` |
+| `maskIBAN(input)` | Mask IBAN for safe display | "CH56 **** **** **** **** 9" |
+| `formatAHV(input)` | AHV/OASI number, grouped | "756.9217.0769.85" |
+| `isValidAHV(input)` | Validate AHV/OASI check digit | `true` |
+| `maskAHV(input)` | Mask AHV number for safe display | "756.****.****.85" |
+| `formatQRReference(input)` | QR-bill/ISR reference, grouped | "21 00000 00003 13947 14300 09017" |
+| `isValidQRReference(input)` | Validate QR-bill/ISR check digit | `true` |
+| `formatUID(input)` | UID/VAT number, grouped | "CHE-116.281.710" |
+| `isValidUID(input)` | Validate UID/VAT check digit | `true` |
+| `isValidSwissPostalCode(input)` | Validate 4-digit postal code range | `true` |
 | `formatSecs(seconds, step?)` | Duration from seconds | "2h30" / "45min" |
 | `formatMinutes(minutes, step?)` | Duration from minutes | "2h30" / "45min" |
 | `formatHours(hours, step?)` | Duration from decimal hours | "2h30" / "45min" |
@@ -74,6 +87,22 @@ import { formatCHF, slugify, clamp } from '@mikespa/kit';
 All `format*` functions that wrap `Intl` accept an optional `locale` parameter
 (defaults to `'fr-CH'`) so consuming projects can override per-call.
 
+For apps with a variable/per-request locale (e.g. a language switcher, or SSR with
+per-request locale), `createFormatters(locale)` returns those same functions
+pre-bound to one locale, so call sites don't repeat `{ locale }` everywhere. It's
+a plain factory — no shared/global state, safe under concurrent requests:
+
+```ts
+import { createFormatters } from '@mikespa/kit/format';
+
+const fmt = createFormatters('de-CH');
+fmt.formatDate(order.date);
+fmt.formatCurrency(order.total);
+```
+
+`createFormatters` binds: `formatDate`, `formatTime`, `formatDateTime`,
+`formatRelative`, `formatNumber`, `formatCompact`, `formatCurrency`, `formatPercent`.
+
 ### `./string`
 
 | Function | Description |