feat(api): add unscoped_relay_count_24h per-node field (#1823)

## What
Adds a per-node API field `unscoped_relay_count_24h` on repeater/room
nodes: the
  number of the node's 24h relay-hops that were unscoped floods
  (route_type == ROUTE_TYPE_FLOOD). A strict subset of relay_count_24h.

  ## Why
A well-configured repeater runs `flood.max.unscoped 0` and should not
rebroadcast
unscoped floods — each one is re-sent by every repeater that hears it,
so one
packet turns into mesh-wide traffic. Exposing this lets clients (the
ArcScope
repeater advisor) detect and flag that base-config problem from observed
packets.

  ## How
Computed like relay_count_24h in both paths (bulk /api/nodes + per-node
detail)
with a route_type==FLOOD filter; reuses the byPathHop index, no
migration. Wired
  into both handlers + OpenAPI schema + unit tests (per-node and bulk).

Co-authored-by: Waydroid Builder <build@waydroid.local>

cmd/server/openapi.go

@@ -172,6 +172,7 @@ func componentSchemas() map[string]interface{} {
 				"relay_active":        map[string]interface{}{"type": "boolean", "description": "Repeater/room only: relayed traffic within the active window."},
 				"relay_count_1h":      map[string]interface{}{"type": "integer", "description": "Repeater/room only: relay-hop appearances in the last hour."},
 				"relay_count_24h":     map[string]interface{}{"type": "integer", "description": "Repeater/room only: relay-hop appearances in the last 24 hours."},
+				"unscoped_relay_count_24h": map[string]interface{}{"type": "integer", "description": "Repeater/room only: subset of relay_count_24h that were unscoped floods (route_type FLOOD). A well-configured repeater sets flood.max.unscoped 0, so a non-trivial count flags a base-config problem."},
 				"last_relayed":        str("Repeater/room only: RFC3339 time this node last appeared as a relay hop."),
 				"relay_window_hours":  map[string]interface{}{"type": "integer", "description": "Repeater/room only, /api/nodes/{pubkey} detail endpoint only: width (hours) of the relay-activity window the relay_count_* values cover."},
 				"traffic_share_score": score01("#672 Traffic axis: share of non-advert traffic relayed through this repeater. Repeater/room only."),