platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/transport_health_refresh_compare.go

@@ -0,0 +1,46 @@
+package app
+
+import (
+	"strings"
+	"time"
+)
+
+func transportShouldPersistHealthSnapshot(prev, next TransportClient, now time.Time) bool {
+	if transportHealthChanged(prev, next) {
+		return true
+	}
+	prevTS, ok := parseTransportHealthLastCheck(prev)
+	if !ok {
+		return true
+	}
+	return now.Sub(prevTS) >= transportHealthPersistMinAge
+}
+
+func transportHealthChanged(prev, next TransportClient) bool {
+	if normalizeTransportStatus(prev.Status) != normalizeTransportStatus(next.Status) {
+		return true
+	}
+	if strings.TrimSpace(prev.Health.LastError) != strings.TrimSpace(next.Health.LastError) {
+		return true
+	}
+	if transportHealthLatencyBucket(prev.Health.LatencyMS) != transportHealthLatencyBucket(next.Health.LatencyMS) {
+		return true
+	}
+	return false
+}
+
+func transportHealthLatencyBucket(ms int) string {
+	if ms <= 0 {
+		return "none"
+	}
+	switch {
+	case ms < 100:
+		return "lt100"
+	case ms < 300:
+		return "100-299"
+	case ms < 800:
+		return "300-799"
+	default:
+		return "ge800"
+	}
+}