Function isValidPhone

isValidPhone(phone: unknown): boolean
Validates any Sri Lankan telephone number (mobile, landline, or recognized short code).
Parameters
- phone: unknown
  Phone number in any common format, for example '077 123 4567' or '+94771234567'. Strings and finite numbers are accepted; other types return a failure without throwing.
Returns boolean
true for a valid mobile, fixed-line, toll-free number, or public short code.
Example
```
isValidPhone('0771234567'); // true
isValidPhone('+94 11 234 5678'); // true
isValidPhone('119'); // true
isValidPhone('12345'); // false
```
- Defined in phone/validator.ts:20