Fix multi-WAN speed test reporting (issue #841)

Speed tests were not being reported correctly for multi-WAN setups
because the device-level speedtest-status field was returning zeros.
The data has moved to a new aggregated dashboard API endpoint.

Changes:
- Add GetSpeedTests() and GetSiteSpeedTests() methods to fetch from
  /v2/api/site/{site}/aggregated-dashboard endpoint
- Create SpeedTestResult data structures to capture per-WAN metrics
- Update Prometheus exporter with new speedtest_* metrics per interface
- Update InfluxDB exporter to write speedtest measurements per WAN
- Update Datadog exporter with unifi.speedtest.* metrics per WAN
- Update metrics collection to include speed test data for all sites

Metrics now include labels/tags for:
- wan_interface: Physical interface (eth8, eth9, etc.)
- wan_group: Logical WAN name (WAN, WAN2, etc.)
- site_name: Site identifier
- source: Controller URL

Gracefully handles older controllers without the new API endpoint.

Fixes #841

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

pkg/datadogunifi/datadog.go

@@ -302,6 +302,10 @@ func (u *DatadogUnifi) loopPoints(r report) {
 		u.switchExport(r, s)
 	}
 
+	for _, st := range m.SpeedTests {
+		u.switchExport(r, st)
+	}
+
 	for _, s := range r.events().Logs {
 		u.switchExport(r, s)
 	}
@@ -348,6 +352,8 @@ func (u *DatadogUnifi) switchExport(r report, v any) { //nolint:cyclop
 		u.batchAlarms(r, v)
 	case *unifi.Anomaly:
 		u.batchAnomaly(r, v)
+	case *unifi.SpeedTestResult:
+		u.batchSpeedTest(r, v)
 	default:
 		u.LogErrorf("invalid export, type=%+v", reflect.TypeOf(v))
 	}

pkg/datadogunifi/speedtest.go

@@ -0,0 +1,39 @@
+package datadogunifi
+
+import (
+	"github.com/unpoller/unifi/v5"
+)
+
+// batchSpeedTest generates Unifi Speed Test datapoints for Datadog.
+// These points can be passed directly to Datadog.
+func (u *DatadogUnifi) batchSpeedTest(r report, st *unifi.SpeedTestResult) {
+	if st == nil {
+		return
+	}
+
+	metricName := metricNamespace("speedtest")
+
+	tags := []string{
+		tag("site_name", st.SiteName),
+		tag("source", st.SourceName),
+		tag("wan_interface", st.InterfaceName),
+		tag("wan_group", st.WANNetworkGroup),
+		tag("network_conf_id", st.NetworkConfID),
+	}
+
+	data := map[string]float64{
+		"download_mbps": st.DownloadMbps.Val,
+		"upload_mbps":   st.UploadMbps.Val,
+		"latency_ms":    st.LatencyMs.Val,
+		"timestamp":     st.Time.Val,
+	}
+
+	if st.WANProviderCapabilities != nil {
+		data["provider_download_kbps"] = st.WANProviderCapabilities.DownloadKbps.Val
+		data["provider_upload_kbps"] = st.WANProviderCapabilities.UploadKbps.Val
+	}
+
+	for name, value := range data {
+		_ = r.reportGauge(metricName(name), value, tags)
+	}
+}