BUG: Improve email truncation logic

[andrinoff]

Describe the bug

The truncateEmail function in tui/inbox.go only truncates the local part of the email address if it's longer than 8 characters. This can lead to very long email strings in the "ALL" view account indicators.

To reproduce

1. Use an account with a long local part or a long domain.
2. View emails in "ALL" view.
3. Observe the account indicator truncation.

Expected behavior

Better truncation that balances local part and domain, or fits within a fixed width more gracefully.

Additional context

func truncateEmail(email string) string {
	parts := strings.Split(email, "@")
	if len(parts) >= 1 && len(parts[0]) > 8 {
		return parts[0][:8] + "..."
	}
	if len(parts) >= 1 {
		return parts[0]
	}
	return email
}

[ritikaa1802]

Hi, I explored this issue and tested the current truncateEmail function.

The current implementation truncates only the local part of the email and completely omits the domain when the local part exceeds 8 characters. This leads to unclear account indicators in the "ALL" view, especially when multiple emails share similar prefixes.

Proposed approach:

• Introduce a maximum length for the entire email string
• Preserve both local part and domain for better readability
• Apply balanced truncation to both parts when necessary

Example:
verylongemail@gmail.com → verylo...@gmail.com

This ensures consistent width while retaining useful identity information.

I’d like to work on this fix. Please let me know if this approach sounds good.

[andrinoff]

@ritikaa1802 , yes, sounds good