[feat] add shared mobile device trust protocol and pairing resources

libs/controller/include/mobile_device_trust.h

@@ -0,0 +1,37 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-11-13
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _MOBILE_DEVICE_TRUST_H_
+#define _MOBILE_DEVICE_TRUST_H_
+
+#include <memory>
+#include <optional>
+#include <string>
+#include <string_view>
+
+namespace crossdesk::mobile_controller {
+// The platform must durably save the seed in its secure store before using it.
+// Existing invalid/unavailable identities must never be replaced automatically.
+class DeviceTrustIdentity {
+ public:
+  explicit DeviceTrustIdentity(std::string_view seed);
+  ~DeviceTrustIdentity();
+  static std::string GeneratePrivateKey();
+  static void ClearSecret(std::string& value);
+  static std::string Advertise(std::string_view host_information);
+  static bool IsChallenge(std::string_view data) noexcept;
+  std::string PairingInfo(const std::string& device_id, const std::string& name) const;
+  const std::string& Fingerprint() const;
+  // nullopt: ordinary control message; empty: unsupported/malformed challenge.
+  std::optional<std::string> ChallengeResponse(std::string_view data,
+      const std::string& device_id, const std::string& name) const noexcept;
+ private:
+  class Impl;
+  std::unique_ptr<Impl> impl_;
+};
+}  // namespace crossdesk::mobile_controller
+
+#endif