Node 0.6.0

Same protocol (3) and room version (1): no event format or validity changes,
and the client API answers as before (GET / now fills operator). The peer
API gains optional fields that older nodes ignore, so 0.6.0 and 0.5.0 nodes
replicate normally. The database gains an origin column on events and
agent_events and two columns on content_gaps, added at startup; older
nodes ignore them, so a rollback to 0.5.0 is safe. Discovery now reads the
chain indexer (data.pocket.network, data.beta.pocket.network), so the
node needs to reach it over HTTPS; without it, it falls back to the chain API.

Added

• Health reports to Discord (SPEC §9.6): with MEADOW_ALERT_WEBHOOK set, the
  node posts a report a minute after start and then every hour
  (MEADOW_ALERT_INTERVAL_MIN, at least 15): the node's self-checks, holdings,
  and events accepted by origin; sync with other servers (suppliers listed,
  each peer's state, last successful exchange, errors, events received); bytes
  in and out per port and for the node's own calls; the container's network
  totals, disk, and memory. Green, amber, or red by level. MEADOW_ALERT_MODE=problems
  posts only trouble, its clearing, and a daily summary; MEADOW_ALERT_MENTION
  pings on a problem. A setting the node can't use is logged and the node
  runs without reports.
• deploy/settings.json: the health report's settings and the source URL,
  for the Pocket Service Manager's Service settings form, with a Test button
  that runs alert-test. The compose file reads them from the server's
  ../settings.env (optional).
• Operator commands peers and alert-test.
• Early discovery (SPEC §11.1): a correctly signed peer request from a node
  this node does not know yet runs discovery at once (at most every 5 minutes)
  instead of waiting up to 30 minutes, so a new supplier is accepted within
  seconds. A signature alone never makes a peer.
• Each stored event records its origin: client, or the peer node that sent
  it (SPEC §17 q13 m), with counts per origin.
• GET / reports the node's supplier operator address without configuration:
  the supplier whose hostname answers /v2/hello with this node's own ID.
  MEADOW_MAIN_OPERATOR and MEADOW_BETA_OPERATOR still override it.
• npm run sim: a replication simulation of many nodes on a simulated network
  and clock, with the real store, peers, replicator, and discovery.

Changed

• Peer penalties are logged with their reason (invalid event and its reason,
  bad report, reply too large, content mismatch), and so is a ban. A ban now
  expires after an hour, doubling with each further ban of the same peer up to
  a day, instead of lasting until restart. Discovery logs peers added, dropped,
  and moved.
• Push pacing (SPEC §11.3): one push in flight per peer, so batches arrive in
  order, and after a failed push the peer waits 1 s, doubling to 5 minutes;
  any successful call ends the wait. A peer refusing at once was pushed to
  about 4 times a second. Failing and recovered pushes are logged once each.
• Incremental anti-entropy (SPEC §11.2, §11.3): /v2/rooms, /v2/agents,
  and /v2/reports take since and the first page carries mark, so a round
  lists only what changed since the last one, with a full comparison first
  and hourly. Older nodes ignore since and keep getting full rounds.
• Agent chains are pulled from this node's own head (/v2/chain with
  after), and served by walking back only that far; after_unknown says
  when to start over from the beginning (a fork).
• Content repair asks for each gap again after 1 minute, doubling to 6 hours,
  instead of every round. The database gains two columns on content_gaps.
• Discovery reads the supplier list from the chain indexer: only each
  supplier's Meadow config (about 300 bytes, against 23 to 47 KB per supplier
  from the chain API), complete at start and every 6 hours, and only what
  changed since the last run in between. The chain API is the fallback when
  the indexer fails or lags. A hostname is asked /v2/hello when new or not
  answering, and otherwise once a day, at most 8 at a time.
  MEADOW_INDEXER_MAIN and MEADOW_INDEXER_BETA override the indexer, or
  off uses only the chain API.
• Anti-entropy runs every 15 seconds instead of every minute, mostly with 4
  stable partners in turn (each kept for a few hours, replaced at once when it
  fails or is dropped), with a random peer one time in ten. A round still
  running makes the next one wait.
• Gossip skips peers waiting after failed pushes, and history pulled to
  complete a push is passed on like the push itself.
• Together, in a 200-node simulation: an event reached every node in 9 s at
  the median and 16 s at the 95th percentile, against 57 s and 229 s.

Fixed

• The container's health check probed both relay ports whatever
  MEADOW_NETWORKS said, so a container running only MainNet was reported
  unhealthy. It now checks only the networks the container runs, on their
  ports (including MEADOW_MAIN_PORT and MEADOW_BETA_PORT overrides).