feat(web): add lib/phone.ts with formatPhone/normalizePhone/zaloHref helpers

- Create apps/web/lib/phone.ts with VN_PHONE_REGEX, normalizePhone,
  formatPhone, and zaloHref helpers
- Deduplicate phone regex: auth.ts and inquiry.ts now import VN_PHONE_REGEX
  from @/lib/phone instead of defining their own local patterns
- Replace raw .replace(/^0/, '84') in inquiry-detail-dialog.tsx and
  lead-detail-dialog.tsx with zaloHref(); use formatPhone() for display

Resolves GOO-209

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/lib/validations/auth.ts

@@ -1,6 +1,6 @@
 import { z } from 'zod';
 
-const phoneRegex = /^(0|\+84)(3[2-9]|5[2689]|7[06-9]|8[1-9]|9[0-9])\d{7}$/;
+import { VN_PHONE_REGEX as phoneRegex } from '@/lib/phone';
 
 export const loginSchema = z.object({
   phone: z

apps/web/lib/validations/inquiry.ts

@@ -1,12 +1,6 @@
 import { z } from 'zod';
 
-/**
- * Vietnamese phone number rule:
- * - 9–11 digits, optional leading +84 or 0.
- * We keep validation pragmatic: whitespace is stripped, then the remaining
- * string must be 9–11 digits (country code / leading zero stripped).
- */
-const PHONE_REGEX = /^(?:\+?84|0)?\d{9,11}$/;
+import { VN_PHONE_REGEX as PHONE_REGEX } from '@/lib/phone';
 
 export const inquiryFormSchema = z.object({
   message: z