fix: include sender display name in From header and default identity selection

- Emails now include the identity display name in the From field so recipients
  see "Name <email>" instead of bare "<email>"
- Primary identity (matching login username) is pre-selected in composer dropdown

components/email/email-composer.tsx

@@ -30,6 +30,7 @@ interface EmailComposerProps {
     body: string;
     draftId?: string;
     fromEmail?: string;
+    fromName?: string;
     identityId?: string;
   }) => void | Promise<void>;
   onClose?: () => void;
@@ -368,7 +369,8 @@ export function EmailComposer({
         currentIdentity?.id,
         fromEmail,
         draftId || undefined,
-        uploadedAttachments
+        uploadedAttachments,
+        currentIdentity?.name || undefined
       );
 
       setDraftId(savedDraftId);
@@ -484,6 +486,7 @@ export function EmailComposer({
         body,
         draftId: finalDraftId || undefined,
         fromEmail,
+        fromName: currentIdentity?.name || undefined,
         identityId: currentIdentity?.id,
       });