webui: upgrade and fix eslint

[nopcoder]

Upgrade Vite to 7.x and Fix ESLint Issues

Summary

• Upgraded Vite build tool from 5.4.8 to 7.1.3 (latest)
• Migrated ESLint from v8 to v9 with flat config format
• Fixed 60+ ESLint errors and warnings for better code quality
• Ensured build fails on ESLint errors (as intended)

Key Changes

Vite Upgrade:

• ✅ Vite: 5.4.8 → 7.1.3
• ✅ TypeScript: 5.3.3 → 5.9.2
• ✅ Removed deprecated splitVendorChunkPlugin
• ✅ Added manual chunk configuration
• ✅ Eliminated TypeScript deprecation warnings

ESLint Modernization:

• ✅ ESLint: 8.57.1 → 9.34.0
• ✅ Migrated from .eslintrc to eslint.config.js (flat config)
• ✅ Updated TypeScript ESLint packages to latest compatible versions
• ✅ Configured build to fail on ESLint errors

Code Quality Fixes:

• ✅ Fixed missing key props in JSX arrays (16 files)
• ✅ Removed accessibility-blocking autoFocus attributes (8+ files)
• ✅ Fixed React Hooks rules violations in ObjectsDiff component
• ✅ Converted anchor elements to proper buttons where appropriate
• ✅ Fixed conditional hook calls and other React best practices

Verification

Build Status: ❌ Correctly fails on remaining ESLint errors (12 remaining)
Tests: ✅ All 13 tests pass
TypeScript: ✅ No compilation errors or deprecation warnings

Remaining Work

• 12 ESLint errors remain in complex components (objects.jsx, metadata.tsx)
• These involve conditional React Hooks that need careful refactoring
• Build properly blocks on these errors until resolved