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/usage-popover.tsx

@@ -25,8 +25,6 @@ type UsageError = {
   message: string;
 };
 
-// Fixed refresh interval (45 seconds)
-const REFRESH_INTERVAL_SECONDS = 45;
 const CLAUDE_SESSION_WINDOW_HOURS = 5;
 
 // Helper to format reset time for Codex
@@ -229,15 +227,6 @@ export function UsagePopover() {
   // Calculate max percentage for header button
   const claudeSessionPercentage = claudeUsage?.sessionPercentage || 0;
 
-  const codexMaxPercentage = codexUsage?.rateLimits
-    ? Math.max(
-        codexUsage.rateLimits.primary?.usedPercent || 0,
-        codexUsage.rateLimits.secondary?.usedPercent || 0
-      )
-    : 0;
-
-  const isStale = activeTab === 'claude' ? isClaudeStale : isCodexStale;
-
   const getProgressBarColor = (percentage: number) => {
     if (percentage >= 80) return 'bg-red-500';
     if (percentage >= 50) return 'bg-yellow-500';