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)

app/[locale]/calendar/page.tsx

@@ -186,7 +186,7 @@ export default function CalendarPage() {
     if (client && enableCalendarTasks && (normalizedViewMode === "tasks" || showTasksOnCalendar)) {
       taskStore.fetchTasks(client);
     }
-  }, [client, enableCalendarTasks, normalizedViewMode, showTasksOnCalendar]);
+  }, [client, enableCalendarTasks, normalizedViewMode, showTasksOnCalendar, taskStore]);
 
   useEffect(() => {
     if (client && calendars.length > 0 && dateRange) {
@@ -704,7 +704,7 @@ export default function CalendarPage() {
     };
     window.addEventListener("keydown", handleKey);
     return () => window.removeEventListener("keydown", handleKey);
-  }, [navigatePrev, navigateNext, goToToday, setViewMode, openCreateModal, showEventModal, detailEvent]);
+  }, [navigatePrev, navigateNext, goToToday, setViewMode, openCreateModal, showEventModal, detailEvent, enableCalendarTasks]);
 
   const visibleEvents = useMemo(() =>
     events.filter((e) => {

app/[locale]/contacts/page.tsx

@@ -122,7 +122,7 @@ export default function ContactsPage() {
   const individuals = useMemo(() => contacts.filter(c => c.kind !== 'group'), [contacts]);
   const selectedContact = contacts.find((c) => c.id === selectedContactId) || null;
   const selectedGroup = selectedGroupId ? contacts.find(c => c.id === selectedGroupId) || null : null;
-  const selectedGroupMembers = selectedGroupId ? getGroupMembers(selectedGroupId) : [];
+  const selectedGroupMembers = useMemo(() => selectedGroupId ? getGroupMembers(selectedGroupId) : [], [selectedGroupId, getGroupMembers]);
 
   // Collect all unique keywords across contacts
   const allKeywords = useMemo(() => {
@@ -307,7 +307,7 @@ export default function ContactsPage() {
     }
   };
 
-  const handleSelectGroup = (id: string) => {
+  const _handleSelectGroup = (id: string) => {
     setSelectedGroupId(id);
     setActiveCategory({ groupId: id });
     setView("group-detail");

app/[locale]/files/page.tsx

@@ -45,7 +45,7 @@ export default function FilesPage() {
     navigateByPath,
     refresh,
     createDirectory,
-    uploadFile,
+    uploadFile: _uploadFile,
     uploadFiles,
     uploadFolder,
     deleteResource,

app/[locale]/login/page.tsx

@@ -11,7 +11,7 @@ import { useThemeStore } from "@/stores/theme-store";
 import { useShallow } from "zustand/react/shallow";
 import { useConfig } from "@/hooks/use-config";
 import { cn } from "@/lib/utils";
-import { Mail, AlertCircle, Loader2, X, Info, Eye, EyeOff, LogIn, Sun, Moon, Monitor, Check, Shield, Play } from "lucide-react";
+import { AlertCircle, Loader2, X, Info, Eye, EyeOff, LogIn, Sun, Moon, Monitor, Check, Shield, Play } from "lucide-react";
 import { discoverOAuth, type OAuthMetadata } from "@/lib/oauth/discovery";
 import { generateCodeVerifier, generateCodeChallenge, generateState } from "@/lib/oauth/pkce";
 import { OAUTH_SCOPES } from "@/lib/oauth/tokens";

app/admin/themes/page.tsx

@@ -3,7 +3,7 @@
 import { useEffect, useState, useRef } from 'react';
 import { Upload, Trash2, Power, Loader2, Palette, Save, Shield } from 'lucide-react';
 import type { SettingsPolicy } from '@/lib/admin/types';
-import { DEFAULT_POLICY, DEFAULT_THEME_POLICY, DEFAULT_FEATURE_GATES } from '@/lib/admin/types';
+import { DEFAULT_POLICY, DEFAULT_THEME_POLICY } from '@/lib/admin/types';
 
 const BUILTIN_THEME_OPTIONS = [
   { id: 'builtin-nord', name: 'Nord' },

app/api/dev-jmap/[...path]/route.ts

@@ -89,7 +89,7 @@ function localDateTime(dayOffset: number, hour: number, minute: number): string
 }
 
 /** Parse a JMAP duration like "PT1H30M", "P1D", "PT45M" into milliseconds. */
-function parseDurationMs(dur: string): number {
+function _parseDurationMs(dur: string): number {
   let ms = 0;
   const dayMatch = dur.match(/(\d+)D/);
   const hourMatch = dur.match(/(\d+)H/);