Approve Claim

Approve a sandboxed claim, transferring skill ownership to the claimant.

Looks up the claim, validates it is in ‘sandbox’ state, then atomically:

• Sets claims.status to 'approved' and records reviewed_at.
• Sets skills.claimed = TRUE and skills.author_id to the claimant.

Args: claim_id: Primary key of the claim to approve. user: Authenticated admin caller. db: Database connection.

Returns: dict with id, status, and message.

Raises: HTTPException 404: Claim does not exist. HTTPException 400: Claim is not in ‘sandbox’ state.