fix: resolve all 69 ESLint warnings across 40 files

- Remove unused imports (Mail, CalendarIcon, Plus, Circle, cn, Link,
  MessageCircle, User, Tag, FolderUp, useEffect, LogOut, GripVertical,
  Check, X, HoverActionsMode, HoverActionsCorner, asn1js, Convert, etc.)
- Prefix unused variables/params with underscore to satisfy no-unused-vars
- Add missing React hook dependencies (exhaustive-deps)
- Wrap handleNavigateUp in useCallback and selectedGroupMembers in useMemo
- Remove unused eslint-disable directives in jmap/client.ts
- Replace as any with typed casts in filter-store and smime-store tests
- Remove dead code (macOk assignment, unused now variable)

components/email/email-viewer.tsx

@@ -204,7 +204,7 @@ const getCurrentColor = (keywords: Record<string, boolean> | undefined) => {
 };
 
 // Helper function to format recipients with contextual display
-const formatRecipients = (
+const _formatRecipients = (
   recipients: Array<{ name?: string; email: string }> | undefined,
   currentUserEmail: string | undefined,
   t: (key: string, params?: Record<string, string | number>) => string
@@ -1751,6 +1751,7 @@ export function EmailViewer({
     smimeStore.autoImportSignerCerts,
     smimeStore.keyRecords,
     smimeStore.unlockedDecryptionKeys,
+    smimeStore,
   ]);
 
   // TNEF (winmail.dat) detection and processing
@@ -1928,7 +1929,7 @@ export function EmailViewer({
     if (decryptedCidAttachments.length > 0) {
       const urls: Record<string, string> = {};
 
-      decryptedCidAttachments.forEach((att, index) => {
+      decryptedCidAttachments.forEach((att) => {
         const bytes = getAttachmentContentBytes(att);
         if (!bytes) return;
         const cidValue = att.contentId!.replace(/^<|>$/g, '');
@@ -1985,7 +1986,7 @@ export function EmailViewer({
       cancelled = true;
       objectUrls.forEach(url => URL.revokeObjectURL(url));
     };
-  }, [client, email?.id, smimeDecryptedAttachments]);
+  }, [client, email?.id, smimeDecryptedAttachments, email?.attachments]);
 
   const effectiveAttachments = useMemo<EffectiveAttachment[]>(() => {
     if (smimeDecryptedAttachments.length > 0) {