Function isEmail

isEmail(text: string): boolean
Validates if a string is a valid email address according to RFC 5322 standards.

This function performs comprehensive validation including:
- Basic email structure (local part + @ + domain)
- Valid characters in local part and domain
- Domain must contain at least one dot
- No consecutive dots
- No trailing dots or hyphens
- Length limits (local part ≤ 64 chars, domain ≤ 255 chars)
- Non-ASCII character rejection
Parameters
- text: string
  The string to validate as an email address
Returns boolean
boolean indicating if the string is a valid email address
Example
```
isEmail('user@example.com')     // true
isEmail('user.name@example.com') // true
isEmail('user+tag@example.com') // true
isEmail('plainaddress')         // false
isEmail('@example.com')         // false
isEmail('user@')               // false
```
- Defined in text/validation/email.ts:26