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>

internal/httpapi/dto.go

@@ -23,6 +23,15 @@ type okResponse struct {
 	OK bool `json:"ok"`
 }
 
+// resultsResponse answers the result-submission endpoints. Ignored counts the
+// submitted checks that were dropped because the address already has its
+// verdict (or the result belongs to an earlier attempt); the sender must not
+// retry them.
+type resultsResponse struct {
+	OK      bool `json:"ok"`
+	Ignored int  `json:"ignored,omitempty"`
+}
+
 type observedIPResponse struct {
 	IP     string `json:"ip"`
 	Source string `json:"source"`