feat: project EmailReadView for email-banner slot, expose auth results

lib/plugin-projection.ts

@@ -0,0 +1,25 @@
+// Projection helpers — convert host-internal types into the read-only views
+// that plugins consume. Keeping this in one place ensures every slot/hook
+// hands plugins the same shape declared in plugin-types.ts.
+
+import type { Email } from '@/lib/jmap/types';
+import type { EmailReadView } from '@/lib/plugin-types';
+
+export function emailToReadView(email: Email): EmailReadView {
+  return {
+    id: email.id,
+    threadId: email.threadId,
+    mailboxIds: Object.keys(email.mailboxIds || {}).filter(k => email.mailboxIds[k]),
+    from: (email.from || []).map(a => ({ name: a.name || '', email: a.email })),
+    to: (email.to || []).map(a => ({ name: a.name || '', email: a.email })),
+    cc: (email.cc || []).map(a => ({ name: a.name || '', email: a.email })),
+    subject: email.subject || '',
+    receivedAt: email.receivedAt,
+    isRead: !!email.keywords?.['$seen'],
+    isFlagged: !!email.keywords?.['$flagged'],
+    hasAttachment: email.hasAttachment,
+    preview: email.preview || '',
+    keywords: Object.keys(email.keywords || {}).filter(k => email.keywords[k]),
+    auth: email.authenticationResults,
+  };
+}

lib/plugin-types.ts

@@ -300,6 +300,17 @@ export interface EmailReadView {
   hasAttachment: boolean;
   preview: string;
   keywords: string[];
+  /**
+   * Parsed Authentication-Results header (SPF, DKIM, DMARC, reverse-DNS).
+   * Absent on stores that didn't parse the header (e.g. bodies not yet
+   * fetched). Mirrors the structured shape exposed by the host.
+   */
+  auth?: {
+    spf?: { result: 'pass' | 'fail' | 'softfail' | 'neutral' | 'none' | 'temperror' | 'permerror'; domain?: string };
+    dkim?: { result: 'pass' | 'fail' | 'policy' | 'neutral' | 'temperror' | 'permerror'; domain?: string; selector?: string };
+    dmarc?: { result: 'pass' | 'fail' | 'none'; policy?: 'reject' | 'quarantine' | 'none'; domain?: string };
+    iprev?: { result: 'pass' | 'fail'; ip?: string };
+  };
 }
 
 export interface DraftView {