feat: add name support to email 'to' field, matching cc/bcc format

[ChiragAgg5k]

Summary

• Extends the to field on the Email message class to accept the same array<array<string,string>> format as cc and bcc, enabling recipient names (e.g. ['email' => '...', 'name' => '...'])
• Fully backward-compatible: plain strings like ['alice@example.com'] are auto-normalized to [['email' => 'alice@example.com']] in the constructor
• Updates all 5 email adapters (Mailgun, SendGrid, SMTP, Resend, Mock) to read to entries via array access, formatting named recipients as "Name <email>" where supported
• Fixes Mailgun address format to use RFC 5322 compliant "Name <email>" (with space before angle bracket)
• All existing tests pass unchanged, proving backward compatibility

Usage

// Existing usage — still works, no changes needed
new Email(to: ['alice@example.com'], ...);

// New: add names to 'to' recipients, same format as cc/bcc
new Email(
    to: [['email' => 'alice@example.com', 'name' => 'Alice']],
    cc: [['email' => 'bob@example.com', 'name' => 'Bob']],
    ...
);

// Mix strings and arrays
new Email(
    to: ['alice@example.com', ['email' => 'bob@example.com', 'name' => 'Bob']],
    ...
);

Test plan

• Run existing test suite — all tests use original string syntax to verify backward compatibility
• Verify each adapter formats named to recipients correctly (e.g. "Alice <alice@example.com>")
• Verify validation rejects entries missing the email key

[greptile-apps]

Greptile Summary

This PR extends the Email message class's to field to accept the same array<array<string,string>> format already used by cc and bcc, enabling named recipients. Plain string entries are auto-normalized in the constructor for full backward compatibility. All five email adapters are updated consistently, and seven new tests cover the new format, mixed inputs, and validation error paths.

• Email.php — introduces normalizeRecipient(), a clean static helper that unifies input handling for to, cc, and bcc and validates non-empty emails at construction time.
• Adapters — each adapter correctly reads $to['email'] and $to['name'] ?? ''; SendGrid uses its native structured object format while the others build \"Name <email>\" strings.
• Mailgun — the h:Reply-To body entry (line 68) is still missing the => assignment operator, making it a numeric-indexed array value rather than a keyed header field. Mailgun will never receive this header.
• PHP 8.1 minimum version bump — the first-class callable syntax (self::normalizeRecipient(...)) requires PHP 8.1; composer.json is updated accordingly, but consumers still on PHP 8.0 will encounter a dependency conflict.

Confidence Score: 4/5

Safe to merge after fixing the Mailgun Reply-To header key bug on line 68.

One P1 finding remains: the Mailgun h:Reply-To entry is a numeric-indexed array value (missing =>), so the Reply-To header is silently dropped for all Mailgun emails. All other changes are well-structured and tested. The P2 display-name quoting note is a hardening suggestion, not a blocker.

src/Utopia/Messaging/Adapter/Email/Mailgun.php — line 68 has a pre-existing bug (missing => on the h:Reply-To entry) that this PR touches but does not fix.

Important Files Changed

Filename	Overview
src/Utopia/Messaging/Messages/Email.php	Adds normalizeRecipient to unify to, cc, and bcc into array<array<string,string>>; validates non-empty email; fully backward-compatible.
src/Utopia/Messaging/Adapter/Email/Mailgun.php	Updated to read to entries as arrays and fixed CC/BCC space formatting; however, the pre-existing h:Reply-To entry is still a numeric-indexed array value (missing =>), meaning the Reply-To header is never sent.
src/Utopia/Messaging/Adapter/Email/Resend.php	Correctly updated to format to recipients with optional name; CC/BCC loops simplified to array_map — safe because normalizeRecipient now guarantees non-empty emails.
src/Utopia/Messaging/Adapter/Email/SMTP.php	Passes $to['email'] and $to['name'] ?? '' to PHPMailer; added ?? [] null-coalescing for CC/BCC result loops — clean and correct.
src/Utopia/Messaging/Adapter/Email/Sendgrid.php	Uses SendGrid's native {email, name} object format for named to recipients, consistent with existing CC/BCC handling.
src/Utopia/Messaging/Adapter/Email/Mock.php	Updated to pass $to['email'] and $to['name'] ?? '' to PHPMailer's addAddress — straightforward and correct.
tests/Messaging/Adapter/Email/EmailTest.php	Adds 7 new tests covering named recipients, mixed formats, plain-string normalization for CC/BCC, and validation error paths — good coverage of the new feature.
composer.json	Bumps minimum PHP requirement from 8.0 to 8.1 to support the first-class callable syntax (self::normalizeRecipient(...)) — intentional but a potentially breaking change for consumers still on PHP 8.0.

_{Reviews (5): Last reviewed commit: "chore: bump PHP requirement to 8.1+, use..." | Re-trigger Greptile}

[greptile-apps]

h:Reply-To entry is a numeric-indexed value, not a keyed header

The array entry on this line is missing the => assignment operator, so the entire string 'h:Reply-To: Name <email>' is stored as a numeric-indexed element (e.g. $body[0]). When form-encoded and sent to Mailgun this becomes 0=h%3AReply-To%3A+... rather than the h:Reply-To custom-header field Mailgun expects. The Reply-To header is therefore silently never forwarded.

This is a pre-existing bug, but this PR already touches the line (adding the RFC 5322 space), making it the natural place to fix it:

Suggested change

	'h:Reply-To: '."{$message->getReplyToName()} <{$message->getReplyToEmail()}>",
	'h:Reply-To' => "{$message->getReplyToName()} <{$message->getReplyToEmail()}>",