v0.4.0

Added

• Access keys with expiration dates: set key expiration during creation (preset or custom date)
  or modify expiration on existing keys, backed by PUT /api/keys/{id}/expiration and updated
  POST /api/keys. Visual status badges show active, expiring soon, and expired states across
  the dashboard.
• Search and sort in the object browser: filter folders and files by case-insensitive substring
  match, and sort by name, size, or last modified date in ascending or descending order, backed
  by search, sortBy, and order query parameters on GET /api/buckets/{id}/objects.
• View and edit object HTTP metadata (Content-Type, Cache-Control, and
  Content-Disposition) in the object browser and preview modal, backed by
  GET and PUT /api/buckets/{id}/objects/metadata.
• Rename, move, and duplicate actions for files and folders in the object browser, backed by
  new POST /api/buckets/{id}/objects/copy and POST /api/buckets/{id}/objects/move endpoints.