Implement Cast Streaming mirroring, DLNA casting, daemon+GUI, and breadd integration

Builds out the full v1 scope: a vendored+patched openscreen subset for
low-latency Cast Streaming (Mirroring receiver 0F5096E8) alongside the
existing Cast V2/HLS and new DLNA/AVTransport casting paths, breadcastd's
Idle/Casting state machine with a private IPC socket, the breadcast GTK4
popup as a thin IPC client, and bread.cast.*/bread.command.cast.* breadd
integration (device discovery, start/stop, mirroring lifecycle events).
Also adds bakery/systemd/Forgejo CI packaging.

Validated end-to-end against a real Chromecast/Google TV: negotiated
Cast Streaming session, live pipeline playback, and daemon+GUI click-to-cast/
stop through the actual popup.

breadcast-caststream-sys/vendor/openscreen/platform/base/interface_info.cc

@@ -0,0 +1,98 @@
+// Copyright 2018 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "platform/base/interface_info.h"
+
+#include <algorithm>
+#include <utility>
+
+namespace openscreen {
+
+InterfaceInfo::InterfaceInfo() = default;
+InterfaceInfo::InterfaceInfo(NetworkInterfaceIndex index,
+                             const uint8_t hardware_address[6],
+                             std::string name,
+                             Type type,
+                             std::vector<IPSubnet> addresses)
+    : index(index),
+      hardware_address{hardware_address[0], hardware_address[1],
+                       hardware_address[2], hardware_address[3],
+                       hardware_address[4], hardware_address[5]},
+      name(std::move(name)),
+      type(type),
+      addresses(std::move(addresses)) {}
+InterfaceInfo::~InterfaceInfo() = default;
+
+IPSubnet::IPSubnet() = default;
+IPSubnet::IPSubnet(IPAddress address, uint8_t prefix_length)
+    : address(std::move(address)), prefix_length(prefix_length) {}
+IPSubnet::~IPSubnet() = default;
+
+IPAddress InterfaceInfo::GetIpAddressV4() const {
+  for (const auto& address : addresses) {
+    if (address.address.IsV4()) {
+      return address.address;
+    }
+  }
+  return IPAddress{};
+}
+
+IPAddress InterfaceInfo::GetIpAddressV6() const {
+  for (const auto& address : addresses) {
+    if (address.address.IsV6()) {
+      return address.address;
+    }
+  }
+  return IPAddress{};
+}
+
+bool InterfaceInfo::HasHardwareAddress() const {
+  return std::any_of(hardware_address.begin(), hardware_address.end(),
+                     [](uint8_t e) { return e != 0; });
+}
+
+std::ostream& operator<<(std::ostream& out, const IPSubnet& subnet) {
+  if (subnet.address.IsV6()) {
+    out << '[';
+  }
+  out << subnet.address;
+  if (subnet.address.IsV6()) {
+    out << ']';
+  }
+  return out << '/' << std::dec << static_cast<int>(subnet.prefix_length);
+}
+
+std::ostream& operator<<(std::ostream& out, InterfaceInfo::Type type) {
+  switch (type) {
+    case InterfaceInfo::Type::kEthernet:
+      out << "Ethernet";
+      break;
+    case InterfaceInfo::Type::kWifi:
+      out << "Wifi";
+      break;
+    case InterfaceInfo::Type::kLoopback:
+      out << "Loopback";
+      break;
+    case InterfaceInfo::Type::kOther:
+      out << "Other";
+      break;
+  }
+
+  return out;
+}
+
+std::ostream& operator<<(std::ostream& out, const InterfaceInfo& info) {
+  out << '{' << info.index << " (a.k.a. " << info.name
+      << "); media_type=" << info.type << "; MAC=" << std::hex
+      << static_cast<int>(info.hardware_address[0]);
+  for (size_t i = 1; i < info.hardware_address.size(); ++i) {
+    out << ':' << static_cast<int>(info.hardware_address[i]);
+  }
+  for (const IPSubnet& ip : info.addresses) {
+    out << "; " << ip;
+  }
+  return out << '}';
+}
+
+}  // namespace openscreen