Add project favorites with star icon and sort-to-top

[JohnRDOrazio]

Context

Users should be able to favorite projects by clicking a star icon on the project card. Favorited projects sort to the top of any list they appear in.

Desired behavior

Star icon

• Empty star icon on every project card (visible to authenticated users only)
• Clicking toggles favorite status (empty star → filled yellow star, and vice versa)
• Optimistic UI update with rollback on API error
• Favorite status is per-user, per-project

Sorting

• Favorited projects sort to the top within any tab (My Projects, Public, Private, All)
• Within the favorited group, maintain the existing sort order (created_at desc)
• Non-favorited projects follow in the normal order

No separate tab

• Favorites do not get their own tab — they appear within existing tabs with sort priority
• The "My Projects" tab is the natural home for quick access to favorited projects

Implementation

Frontend

• Add star icon to ProjectCard component
• Call POST /api/v1/projects/{id}/favorite or DELETE on toggle
• Read is_favorited from project response to render filled/empty star
• Sort favorited projects to top in the project list

Backend dependency

• Requires Add project favorites: database table and API endpoints ontokit-api#30 (database table + API endpoints)

Related

• Add project favorites: database table and API endpoints ontokit-api#30 — backend: project favorites table and API