Serve the mission projection receipt for mission_id.

The response is a deterministic function of the mission's ledger file: the same ledger bytes serve the same status and mission_status_hash from any server, so two operators cross-check byte for byte. ledger_verified=false (with overall=unverified) marks a chain that no longer recomputes -- the timeline still renders, but the screen must show the unverified banner instead of trusting the state.