Unix Domain Socket auto discovery (#833)

This PR adds end-to-end Unix domain socket (UDS) support, allowing zen CLI to discover and connect to UDS-only servers automatically.

- **`unix://` URI scheme in zen CLI**: The `-u` / `--hosturl` option now accepts `unix:///path/to/socket` to connect to a zenserver via a Unix domain socket instead of TCP.
- **Per-instance shared memory for extended server info**: Each zenserver instance now publishes a small shared memory section (keyed by SessionId) containing per-instance data that doesn't fit in the fixed-size ZenServerEntry -- starting with the UDS socket path. This is a 4KB pagefile-backed section on Windows (`Global\ZenInstance_{sessionid}`) and a POSIX shared memory object on Linux/Mac (`/UnrealEngineZen_{sessionid}`).
- **Client-side auto-discovery of UDS servers**: `zen info`, `zen status`, etc. now automatically discover and prefer UDS connections when a server publishes a socket path. Servers running with `--no-network` (UDS-only) are no longer invisible to the CLI.
- **`kNoNetwork` flag in ZenServerEntry**: Servers started with `--no-network` advertise this in their shared state entry. Clients skip TCP fallback for these servers, and display commands (`ps`, `status`, `top`) show `-` instead of a port number to indicate TCP is not available.

3 files changed, 8 insertions, 3 deletions

diff --git a/src/zenhttp/clients/httpclientcpr.cpp b/src/zenhttp/clients/httpclientcpr.cpp
index a0f5cc38f..a52b8f74b 100644
--- a/src/zenhttp/clients/httpclientcpr.cpp
+++ b/src/zenhttp/clients/httpclientcpr.cpp
@@ -7,6 +7,7 @@
 #include <zencore/compactbinarypackage.h>
 #include <zencore/compactbinaryutil.h>
 #include <zencore/compress.h>
+#include <zencore/filesystem.h>
 #include <zencore/iobuffer.h>
 #include <zencore/iohash.h>
 #include <zencore/session.h>
@@ -513,7 +514,7 @@ CprHttpClient::AllocSession(const std::string_view				 BaseUrl,
 
 	if (!ConnectionSettings.UnixSocketPath.empty())
 	{
-		CprSession->SetUnixSocket(cpr::UnixSocket(ConnectionSettings.UnixSocketPath));
+		CprSession->SetUnixSocket(cpr::UnixSocket(PathToUtf8(ConnectionSettings.UnixSocketPath)));
 	}
 
 	if (ConnectionSettings.InsecureSsl || !ConnectionSettings.CaBundlePath.empty())
diff --git a/src/zenhttp/clients/httpclientcurl.cpp b/src/zenhttp/clients/httpclientcurl.cpp
index 0dbd5b975..ec9b7bac6 100644
--- a/src/zenhttp/clients/httpclientcurl.cpp
+++ b/src/zenhttp/clients/httpclientcurl.cpp
@@ -8,6 +8,7 @@
 #include <zencore/compactbinaryutil.h>
 #include <zencore/compress.h>
 #include <zencore/except.h>
+#include <zencore/filesystem.h>
 #include <zencore/iobuffer.h>
 #include <zencore/iohash.h>
 #include <zencore/session.h>
@@ -808,7 +809,8 @@ CurlHttpClient::AllocSession(std::string_view ResourcePath, const KeyValueMap& P
 	// Unix domain socket
 	if (!m_ConnectionSettings.UnixSocketPath.empty())
 	{
-		curl_easy_setopt(Handle, CURLOPT_UNIX_SOCKET_PATH, m_ConnectionSettings.UnixSocketPath.c_str());
+		std::string SocketPathUtf8 = PathToUtf8(m_ConnectionSettings.UnixSocketPath);
+		curl_easy_setopt(Handle, CURLOPT_UNIX_SOCKET_PATH, SocketPathUtf8.c_str());
 	}
 
 	// Build URL with parameters
diff --git a/src/zenhttp/clients/httpwsclient.cpp b/src/zenhttp/clients/httpwsclient.cpp
index 2d566ae86..fbae9f5fe 100644
--- a/src/zenhttp/clients/httpwsclient.cpp
+++ b/src/zenhttp/clients/httpwsclient.cpp
@@ -5,6 +5,8 @@
 #include "../servers/wsframecodec.h"
 
 #include <zencore/base64.h>
+#include <zencore/filesystem.h>
+#include <zencore/fmtutils.h>
 #include <zencore/logging.h>
 #include <zencore/string.h>
 
@@ -155,7 +157,7 @@ struct HttpWsClient::Impl
 			}
 		});
 
-		asio::local::stream_protocol::endpoint Endpoint(m_Settings.UnixSocketPath);
+		asio::local::stream_protocol::endpoint Endpoint(PathToUtf8(m_Settings.UnixSocketPath));
 		m_UnixSocket->async_connect(Endpoint, [this](const asio::error_code& Ec) {
 			if (Ec)
 			{