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

selective-vpn-api/app/smartdns_runtime_state.go

@@ -0,0 +1,65 @@
+package app
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+func normalizeSmartDNSRuntimeState(st smartDNSRuntimeState) smartDNSRuntimeState {
+	if st.Version <= 0 {
+		st.Version = smartdnsRuntimeStateVersion
+	}
+	return st
+}
+
+func inferSmartDNSRuntimeEnabled() bool {
+	enabled, err := smartDNSRuntimeEnabledFromConfig()
+	if err != nil {
+		// Keep historical behavior on first run when config is unavailable.
+		return true
+	}
+	return enabled
+}
+
+func loadSmartDNSRuntimeState(logf func(string, ...any)) smartDNSRuntimeState {
+	if data, err := os.ReadFile(smartdnsRTPath); err == nil {
+		var st smartDNSRuntimeState
+		if json.Unmarshal(data, &st) == nil {
+			return normalizeSmartDNSRuntimeState(st)
+		}
+		if logf != nil {
+			logf("smartdns runtime: invalid state json at %s, rebuilding", smartdnsRTPath)
+		}
+	}
+
+	st := smartDNSRuntimeState{
+		Version:   smartdnsRuntimeStateVersion,
+		Enabled:   inferSmartDNSRuntimeEnabled(),
+		UpdatedAt: time.Now().UTC().Format(time.RFC3339),
+	}
+	_ = saveSmartDNSRuntimeState(st)
+	return st
+}
+
+func saveSmartDNSRuntimeState(st smartDNSRuntimeState) error {
+	st = normalizeSmartDNSRuntimeState(st)
+	st.UpdatedAt = time.Now().UTC().Format(time.RFC3339)
+	data, err := json.MarshalIndent(st, "", "  ")
+	if err != nil {
+		return err
+	}
+	if err := os.MkdirAll(filepath.Dir(smartdnsRTPath), 0o755); err != nil {
+		return err
+	}
+	tmp := smartdnsRTPath + ".tmp"
+	if err := os.WriteFile(tmp, data, 0o644); err != nil {
+		return err
+	}
+	return os.Rename(tmp, smartdnsRTPath)
+}
+
+func smartDNSRuntimeEnabled() bool {
+	return loadSmartDNSRuntimeState(nil).Enabled
+}