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/identity/identity-manager-modal.tsx

@@ -45,7 +45,7 @@ export function IdentityManagerModal({ isOpen, onClose }: IdentityManagerModalPr
 
   const client = useAuthStore((state) => state.client);
   const identities = useIdentityStore((state) => state.identities);
-  const preferredPrimaryId = useIdentityStore((state) => state.preferredPrimaryId);
+  const _preferredPrimaryId = useIdentityStore((state) => state.preferredPrimaryId);
   const setPreferredPrimary = useIdentityStore((state) => state.setPreferredPrimary);
   const syncIdentities = useSyncIdentities();