Remove points from posting detail UI

[Copilot]

The posting flow still exposed a points value on the post detail screen, despite that value being deprecated from this surface. This updates the posting screen path to stop wiring points into post rendering.

• Posting UI surface

  • Removed the points prop from the PostCard render in frontend/app/(logged-in)/posting/[id].tsx.
  • Kept all other post metadata and interactions unchanged (task/category, reactions, comments, kudos, media, etc.).

• Scope / behavior

  • Change is limited to the posting detail flow UI path.
  • Backend/user stat handling is unchanged; this PR only removes visibility wiring on the posting screen.

<PostCard
  // ...
  priority="low"
  timeTaken={0}
  category={post.task?.category?.name}
  taskName={post.task?.content}
/>

• Fixes Remove "points" from posting screen #389