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/smime-sign.ts

@@ -1,6 +1,5 @@
 import * as asn1js from 'asn1js';
 import * as pkijs from 'pkijs';
-import { Convert } from 'pvtsutils';
 import { parseCertificateDer } from './certificate-utils';
 
 /**
@@ -44,13 +43,13 @@ export async function smimeSign(
   const algorithm = privateKey.algorithm;
   const hashAlgorithm = 'SHA-256';
 
-  let signAlg: string;
+  let _signAlg: string;
   if (algorithm.name === 'RSASSA-PKCS1-v1_5' || algorithm.name === 'RSA-PSS') {
-    signAlg = algorithm.name;
+    _signAlg = algorithm.name;
   } else if (algorithm.name === 'ECDSA') {
-    signAlg = 'ECDSA';
+    _signAlg = 'ECDSA';
   } else {
-    signAlg = 'RSASSA-PKCS1-v1_5';
+    _signAlg = 'RSASSA-PKCS1-v1_5';
   }
 
   // Sign