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)

lib/smime/__tests__/certificate-utils.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, vi, beforeAll } from 'vitest';
+import { describe, it, expect, beforeAll } from 'vitest';
 import {
   pemToDer,
   derToPem,

lib/smime/__tests__/key-storage.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { describe, it, expect } from 'vitest';
 import 'fake-indexeddb/auto';
 
 // Each test file gets a fresh global indexedDB via fake-indexeddb/auto.

lib/smime/__tests__/smime-store.test.ts

@@ -21,7 +21,7 @@ vi.mock('@/lib/smime/certificate-utils', () => ({
 }));
 
 import { useSmimeStore } from '@/stores/smime-store';
-import { listKeyRecords, listPublicCerts, saveKeyRecord, deleteKeyRecord, savePublicCert, deletePublicCert } from '@/lib/smime/key-storage';
+import { listKeyRecords, listPublicCerts, saveKeyRecord, deleteKeyRecord, deletePublicCert } from '@/lib/smime/key-storage';
 import { importPkcs12, unlockPrivateKey } from '@/lib/smime/pkcs12-import';
 import type { SmimeKeyRecord, SmimePublicCert } from '@/lib/smime/types';
 
@@ -128,7 +128,7 @@ describe('smime-store', () => {
     it('imports and adds key record', async () => {
       vi.mocked(importPkcs12).mockResolvedValue({
         keyRecord: mockKeyRecord,
-        certInfo: {} as any,
+        certInfo: {} as unknown as import('@/lib/smime/types').CertificateInfo,
       });
 
       const result = await useSmimeStore.getState().importPKCS12(