Show egress/ingress levels in the registry; freeze checks at the verdict

Registry: the "last result" column now also shows, per level (egress,
ingress), how many of the recorded checks of the latest cycle succeeded, split
by check family (tcp-22 and tcp-443 are both "tcp"). One grouped query per
chunk of addresses; new fields last_cycle_id, egress, ingress in
GET /admin/registry; the dashboard renders them under the verdict.

Verdict integrity (migration 0010):
- the prober is handed an address once per site and attempt, not on every
  poll, so results are no longer overwritten by later probe rounds;
- UpsertCheckIfOpen refuses writes once the address is aggregating or has its
  verdict, or for an older attempt; senders get {"ok":true,"ignored":N} and a
  result_dropped event is recorded;
- the checking window counts from checking_started_at, not from assigned_at;
- checks.recorded_at (server clock) and checks.after_verdict (flag for rows
  written after the verdict in existing data);
- the verdict rule is a pure function (computeVerdict) and the aggregated
  event carries the egress/ingress check counts.

Rebuilt bin/control-api and bin/admin-dashboard to match. Plans and summaries
are in docs/changes; README, API, USAGE, DASHBOARD and DIAGRAMS are updated.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

bin/SHA256SUMS

@@ -1,4 +1,4 @@
-9447699d9eed4b9fb5d417769fc868986a10357ec633ec3742883b3002aaafc3  control-api
+657d24d49686f04d3e9d9e431bb56ba8d7e2b3f6d865059de8315eceee6df53a  control-api
 9fb6608b84143f7c4f318f3cc92dcd9f95c7831d627b23d67cce5a5908ced704  validator-agent
 3e9e14dbb361ee76aaad7c1da6864b3ea111e0ed151403f904b12485631bbf75  prober
-d72234688eb1954dbff420ca1c8e83b83ceab561b18a0336af0f73fe4d9ac8be  admin-dashboard
+8c636afb4f68b461376a1f5a010faa72cc0b0f17adf55611e9d924936d6fe115  admin-dashboard