Reduce metrics cardinality, bookie consistency check, antithesis assertions

[gorbak25]

• Introduces a new admin command (CheckBookieConsistency) that rebuilds bookie state from DB via BookedVersions::load_all_from_conn and compares it against in-memory bookie state to detect consistency drift.
• Runs the corrosion healtcheck on antithesis. This should catch sync performance degradation in antithesis.
• Changes corro.db.gaps.sum to bucket by peer_state instead of actor_id to avoid high-cardinality series.
• Introduces corro.db.buffered.changes.v2.total and corro.db.buffered.changes.v2.oldest_age_seconds for buffered-change visibility with bounded cardinality. The metric got renamed so the old metrics don't slow down grafana.
• Removes high-cardinality transport per-address metrics; keeps delta tracking and logs only increases for cwnd, congestion_events, and black_holes_detected.
• Buckets transport/connect/send metrics by traffic class (sync, broadcast, foca) and wires traffic tagging through open_bi, send_uni, and send_datagram. This way we can distinguish if sync or broadcast uses up more traffic. This tagging relies on the assumption that:
  • open_bi is used primarily in sync
  • send_datagram by FOCA/SWIM
  • send_uni by broadcast traffic
• Adds v2 to the name of some metrics to distinguish the old high cardinality series from the new low cardinality ones
• Introduces corro.transport.rtt.v2.seconds which is an histogram of the rtt of peers

[somtochiama]

LGTM @gorbak25 !