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/board-view/shared/model-selector.tsx

@@ -1,13 +1,12 @@
-// @ts-nocheck
+// @ts-nocheck - model selector with provider-specific model options and validation
 import { Label } from '@/components/ui/label';
 import { Badge } from '@/components/ui/badge';
 import { Brain, AlertTriangle } from 'lucide-react';
 import { AnthropicIcon, CursorIcon, OpenAIIcon } from '@/components/ui/provider-icon';
 import { cn } from '@/lib/utils';
-import type { ModelAlias } from '@/store/app-store';
 import { useAppStore } from '@/store/app-store';
 import { useSetupStore } from '@/store/setup-store';
-import { getModelProvider, PROVIDER_PREFIXES, stripProviderPrefix } from '@automaker/types';
+import { getModelProvider } from '@automaker/types';
 import type { ModelProvider } from '@automaker/types';
 import { CLAUDE_MODELS, CURSOR_MODELS, ModelOption } from './model-constants';
 import { useEffect } from 'react';