feat(email): envelope override in sendRaw + suppressed in EmailSendResult type

Adds an optional `envelope` field to SendMailOptions so callers can set
transport recipients independently of the visible To/Cc headers (used by
the email-send driver for per-recipient deliveries), and adds the
`suppressed: string[]` field to the public EmailSendResult typing to
match the driver's documented result.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/backend/clients/email/EmailClient.ts

@@ -45,6 +45,11 @@ export interface SendMailOptions {
     to: string;
     cc?: string;
     bcc?: string;
+    /** Optional transport recipients when they differ from visible headers. */
+    envelope?: {
+        from?: string;
+        to: string;
+    };
     subject: string;
     html?: string;
     text?: string;

src/puter-js/types/modules/email.d.ts

@@ -36,10 +36,12 @@ export interface EmailSendOptions {
 }
 
 export interface EmailSendResult {
-    /** Transport message id, when the mail server reports one. */
+    /** First transport message id reported for this send, when available. */
     messageId: string | null;
     /** Total charge for this send, in microcents. */
     cost: number;
+    /** Recipients omitted because they opted out of this sender's mail. */
+    suppressed: string[];
 }
 
 /**