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/dashboard/dto.go

@@ -264,8 +264,47 @@ type registryItem struct {
 	LastCheckedAt *time.Time `json:"last_checked_at"`
 	InQueue       bool       `json:"in_queue"`
 	CurrentState  string     `json:"current_state"`
+	// LastCycleID is the cycle counted by Egress and Ingress (0 = no checks).
+	LastCycleID int         `json:"last_cycle_id"`
+	Egress      levelResult `json:"egress"`
+	Ingress     levelResult `json:"ingress"`
 }
 
+// levelResult is "ok of total" recorded checks of one level (egress or
+// ingress) in the last cycle, split by check family — see httpapi's
+// levelResultDTO.
+type levelResult struct {
+	Total  int        `json:"total"`
+	OK     int        `json:"ok"`
+	ByType []typeStat `json:"by_type"`
+}
+
+type typeStat struct {
+	Type  string `json:"type"`
+	Total int    `json:"total"`
+	OK    int    `json:"ok"`
+}
+
+// statClass picks the colour of an "ok of total" figure: all checks passed,
+// none passed, some passed, or nothing recorded.
+func statClass(ok, total int) string {
+	switch {
+	case total == 0:
+		return "none"
+	case ok == total:
+		return "ok"
+	case ok == 0:
+		return "fail"
+	}
+	return "part"
+}
+
+// Class is the CSS modifier for the level's total.
+func (l levelResult) Class() string { return statClass(l.OK, l.Total) }
+
+// Class is the CSS modifier for one check family.
+func (t typeStat) Class() string { return statClass(t.OK, t.Total) }
+
 type registryHistoryResponse struct {
 	Registry registryItem `json:"registry"`
 	Checks   []check      `json:"checks"`