feat: implemented bounty card store

[Ekep-Obasi]

Describe your changes

Issue ticket number and link: https://community.sphinx.chat/bounty/3079

https://www.loom.com/share/443426a3990841988cd044eb6258a10e?sid=80f36b1e-d876-4335-becb-5a3093182e42

BountyCard Store Usage Patterns

// 1. Initialize store with workspace
const bountyStore = useBountyCardStore(workspaceId);

// 2. Access bounty data
const { bountyCards, loading, error } = bountyStore;

Common Usage Patterns

1. Workspace View Implementation

const WorkspaceView = observer(() => {
  const { uuid } = useParams<{ uuid: string }>();
  const bountyStore = useBountyCardStore(uuid);

  return (
    <div>
      {bountyStore.loading ? (
        <LoadingSpinner />
      ) : (
        <BountyList cards={bountyStore.bountyCards} />
      )}
    </div>
  );
});

2. Handling Workspace Switches

useEffect(() => {
  if (newWorkspaceId) {
    bountyStore.switchWorkspace(newWorkspaceId);
  }
}, [newWorkspaceId]);

3. Implementing Pagination

// Load more button implementation
const LoadMoreButton = observer(() => {
  const hasMorePages = 
    bountyStore.pagination.currentPage * bountyStore.pagination.pageSize < 
    bountyStore.pagination.total;

  return hasMorePages ? (
    <button onClick={() => bountyStore.loadNextPage()}>
      Load More
    </button>
  ) : null;
});

4. Error Handling

const WorkspaceError = observer(() => {
  if (!bountyStore.error) return null;

  return (
    <div className="error-container">
      <p>{bountyStore.error}</p>
      <button onClick={() => bountyStore.loadWorkspaceBounties()}>
        Retry
      </button>
    </div>
  );
});