Scaffold C++20 screencast project with Meson, agent workflow, and phase plan

include/screencast/network/discovery.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <functional>
+#include <memory>
+#include <string>
+
+namespace sc {
+
+struct DiscoveredPeer {
+    std::string service_name;
+    std::string host;
+    uint16_t signaling_port = 0;
+};
+
+class DiscoveryService {
+  public:
+    using PeerCallback = std::function<void ( const DiscoveredPeer & )>;
+
+    virtual ~DiscoveryService () = default;
+
+    // Announce this peer on the LAN.
+    virtual bool announce ( const std::string &service_name, uint16_t signaling_port ) = 0;
+
+    // Browse for peers; callback is invoked for each newly found service.
+    virtual bool browse ( PeerCallback on_peer ) = 0;
+
+    virtual void stop () = 0;
+};
+
+class DiscoveryFactory {
+  public:
+    static std::unique_ptr<DiscoveryService> create_avahi ();
+};
+
+}  // namespace sc