Registry and Analytics: run, subnet, direction and protocol filters, successes-by-target chart

Registry (/registry):
- filters by run (slice by the address's cycle in that run), subnet
  (drop-down of configured subnets), direction (egress/ingress) and
  protocol (icmp, tcp, ssh, https, tls); status in scope is computed over
  the narrowed checks
- chart "successful checks per target (egress) / site (ingress)" when both
  direction and protocol are chosen; a row opens the list of addresses
  (dialog, CSV)
- API: direction/protocol parameters and run in GET /admin/registry,
  GET /admin/registry/breakdown and /breakdown/list
- subnet filter passes ids as one JSON parameter (SQLite variable limit)

Analytics (/analytics):
- subnet filter recomputes the whole page over the addresses of the run
  inside the subnet; only their checks are read; cache per run and subnet
- direction and protocol focus the page; with both set the registry chart
  is shown
- subnet parameter in GET /admin/analytics/runs/{id} and lists (JSON, CSV)

Docs: plans and summaries in docs/changes, README, API, USAGE.

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

internal/httpapi/auth_test.go

@@ -97,8 +97,8 @@ func TestRouteTableIsClassified(t *testing.T) {
 			t.Fatalf("admin route %q is %s, want admin", rt.Pattern, rt.Access)
 		}
 	}
-	if counts["admin"] != 41 || counts["agent"] != 5 || counts["open"] != 8 {
-		t.Fatalf("access counts = %v, want admin=41 agent=5 open=8", counts)
+	if counts["admin"] != 43 || counts["agent"] != 5 || counts["open"] != 8 {
+		t.Fatalf("access counts = %v, want admin=43 agent=5 open=8", counts)
 	}
 }