chore: Fix all lint errors and remove unused code

- Fix 75 ESLint errors by updating eslint.config.mjs:
  - Add missing browser globals (MouseEvent, AbortController, Response, etc.)
  - Add Vite define global (__APP_VERSION__)
  - Configure @ts-nocheck to require descriptions
  - Add no-unused-vars rule for .mjs scripts

- Fix runtime bug in agent-output-modal.tsx (setOutput -> setStreamedContent)

- Remove ~120 unused variable warnings across 97 files:
  - Remove unused imports (React hooks, lucide icons, types)
  - Remove unused constants and variables
  - Remove unused function definitions
  - Prefix intentionally unused parameters with underscore

- Add descriptions to all @ts-nocheck comments (25 files)

- Clean up misc issues:
  - Remove invalid deprecation plugin comments
  - Fix eslint-disable comment placement
  - Add missing RefreshCw import in code-view.tsx

Reduces lint warnings from ~300 to 67 (all remaining are no-explicit-any)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/ui/src/components/views/setup-view/steps/claude-setup-step.tsx

@@ -38,11 +38,6 @@ interface ClaudeSetupStepProps {
   onSkip: () => void;
 }
 
-interface ClaudeSetupContentProps {
-  /** Hide header and navigation for embedded use */
-  embedded?: boolean;
-}
-
 type VerificationStatus = 'idle' | 'verifying' | 'verified' | 'error';
 
 // Claude Setup Step
@@ -272,12 +267,6 @@ export function ClaudeSetupStep({ onNext, onBack, onSkip }: ClaudeSetupStepProps
   const isApiKeyVerified = apiKeyVerificationStatus === 'verified';
   const isReady = isCliVerified || isApiKeyVerified;
 
-  const getAuthMethodLabel = () => {
-    if (isApiKeyVerified) return 'API Key';
-    if (isCliVerified) return 'Claude CLI';
-    return null;
-  };
-
   // Helper to get status badge for CLI
   const getCliStatusBadge = () => {
     if (cliVerificationStatus === 'verified') {

apps/ui/src/components/views/setup-view/steps/cli-setup-step.tsx

@@ -1,4 +1,4 @@
-// @ts-nocheck
+// @ts-nocheck - CLI setup wizard with step validation and setup store state
 import { useState, useEffect, useCallback } from 'react';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';

apps/ui/src/components/views/setup-view/steps/codex-setup-step.tsx

@@ -1,4 +1,4 @@
-// @ts-nocheck
+// @ts-nocheck - Codex setup wizard with Electron API integration
 import { useMemo, useCallback } from 'react';
 import { useSetupStore } from '@/store/setup-store';
 import { getElectronAPI } from '@/lib/electron';

apps/ui/src/components/views/setup-view/steps/providers-setup-step.tsx

@@ -229,8 +229,6 @@ function ClaudeContent() {
     claudeAuthStatus?.method === 'api_key_env';
 
   const isCliAuthenticated = claudeAuthStatus?.method === 'cli_authenticated';
-  const isApiKeyAuthenticated =
-    claudeAuthStatus?.method === 'api_key' || claudeAuthStatus?.method === 'api_key_env';
   const isReady = claudeCliStatus?.installed && claudeAuthStatus?.authenticated;
 
   return (
@@ -803,7 +801,6 @@ function CodexContent() {
   };
 
   const isReady = codexCliStatus?.installed && codexAuthStatus?.authenticated;
-  const hasApiKey = !!apiKeys.openai || codexAuthStatus?.method === 'api_key';
 
   return (
     <Card className="bg-card border-border">