.biz Hotel Improvements

Request: Apply email validation (for both Vendor and Seller)

- Validation conditions
1) Automatic Trim of Spaces
- If there are spaces before or after the input value, they must be automatically removed on submission.
- Do not validate with spaces included. First apply to trim, then follow the email validation process like `user@domain.com`.

2) Basic Format Conditions
- Must contain the `@' character
- After `@` there must be a '.'(dot).
- This ensures that the email address at least follows the `local@domain.tld` format.

3) Length Restrictions (based on RFC)
- Total length: Up to 254 characters — following the RFC maximum length of 254.
- Local part (before "@"): Up to 64 characters — based on the standard specification.
- Domain part: Generally up to 255 characters, but restricted to 254 in total length. Each domain label can be up to 63 characters.

- Path (for both Vendor and Seller)
1. Sign up > 2.Corperation Info
- input : Rep. email
2. Sign up > 3. Administrator registration
- input : ID, Email
3. Member list > Staff list > [New] modal
- input : ID, Email

- Validation error screen: When the user clicks [Save] without meeting the validation conditions, show orange color on the input stroke and placeholder (same as existing implementation — see attached screenshot).