feat(ui): Add favorites/pinned applications with localStorage persistence

[Copilot]

Users can now mark applications as favorites for quick access. Favorites appear at the top of the applications list and persist across sessions.

Implementation

State Management Hook (useFavorites.js)

• Native Preact hooks (useState/useEffect) with functional updates for concurrent changes
• localStorage format: { version: 1, favorites: ["namespace/resourceName", ...] }
• Storage events for cross-tab synchronization, handling both updates and clears
• Export/import via exportFavorites() and importFavorites(jsonString)

const { isFavorite, toggleFavorite } = useFavorites();

// Application ID generation ensures uniqueness
getApplicationId(app) // => "namespace/resourceName"

UI Integration

• Star icon in Application component (edit mode only)
  • Filled star for favorites, outline for non-favorites
  • aria-pressed state, descriptive aria-label for screen readers
• ApplicationGroupList filters favorites into top section (no heading)
• separateFavoritesFromGroups() helper for clean separation logic

Accessibility

• Full keyboard navigation (Tab, Enter, Space)
• Proper ARIA semantics on star toggle button
• High contrast mode compatible

Testing

• 23 tests for useFavorites hook covering all methods and edge cases
• 7 additional tests for Application component star icon behavior
• All 248 existing tests pass
• CodeQL: no security issues

Original prompt

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This section details on the original issue you should resolve

<issue_title>feat(ui): Favorites/Pinned Applications</issue_title>
<issue_description>## Overview

Enable users to mark applications as favorites for quick access, improving productivity for users managing many applications.

Features

Core Functionality

• Star/Pin Applications: Toggle favorite status via star icon on application cards. The star icon shows up in edit mode only.
• Quick Access: Favorites appear before regular application groups but it has no heading for the section.

User Experience

• Easy Management: Unfavorite via star icon
• Cross-Tab Sync: Use storage events to keep favorites synchronized across browser tabs
• Data Portability: Export/import favorites in JSON format, along with display preferences for backup and sharing
• Persistent Storage: Local storage per user, preserving favorites across sessions

Benefits

• Personalized experience for frequently accessed applications
• Reduced search and scroll time
• Improved productivity for users with 20+ applications

---

User Documentation

• Update user guide with favorites feature
• Document export/import process
• Add screenshots

---

Technical Considerations

Data Persistence

• Primary Key: Application ID (from backend)
• Storage Format: { "version": 1, "favorites": ["app-id-1", "app-id-2"] }
• Future Enhancement: Backend persistence for multi-device sync

Browser Compatibility

• localStorage supported in all modern browsers
• Graceful degradation if localStorage unavailable (in-memory fallback)

---

Acceptance Criteria

• Users can star/unstar applications with a single click
• Favorites section appears at the top
• Favorites persist across page reloads
• Favorites sync across browser tabs in real-time
• Export/import functions work correctly with valid JSON
• All interactions are keyboard accessible
• Screen readers announce favorite state changes
• Unit test coverage ≥80% for new code
• No visual regressions in existing application cards
• Feature works in light and dark themes
• High contrast mode supported

---

Future Enhancements

• Backend persistence for favorites (sync across devices)
• Drag-and-drop reordering of favorites
• Favorite groups/collections
• Search within favorites
• Bulk favorite/unfavorite operations</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes feat(ui): Favorites/Pinned Applications #398

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[github-actions]

Test Results - JVM

857 tests  +50   849 ✅ +50   53s ⏱️ -1s
 69 suites + 1     8 💤 ± 0 
 49 files   ± 0     0 ❌ ± 0 

Results for commit f78ab38. ± Comparison against base commit b7a7613.

♻️ This comment has been updated with latest results.

[github-actions]

Test Results - Native

857 tests  +50   849 ✅ +50   55s ⏱️ -1s
 69 suites + 1     8 💤 ± 0 
 49 files   ± 0     0 ❌ ± 0 

Results for commit cb4a11b. ± Comparison against base commit b7a7613.

♻️ This comment has been updated with latest results.

[github-actions]

Pull Request closed and locked due to lack of activity.
If you'd like to build on this closed PR, you can clone it using this method: https://stackoverflow.com/a/14969986
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