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.

1 files changed, 12 insertions, 12 deletions

diff --git a/src/zen/cmds/workspaces_cmd.cpp b/src/zen/cmds/workspaces_cmd.cpp
index af265d898..220ef6a9e 100644
--- a/src/zen/cmds/workspaces_cmd.cpp
+++ b/src/zen/cmds/workspaces_cmd.cpp
@@ -86,7 +86,7 @@ namespace {
 WorkspaceCommand::WorkspaceCommand()
 {
 	m_Options.add_options()("h,help", "Print help");
-	m_Options.add_option("", "u", "hosturl", "Host URL", cxxopts::value(m_HostName)->default_value(""), "<hosturl>");
+	m_Options.add_option("", "u", "hosturl", kHostUrlHelp, cxxopts::value(m_HostName)->default_value(""), "<hosturl>");
 	m_Options.add_options()("system-dir", "Specify system root", cxxopts::value(m_SystemRootDir));
 	m_Options.add_option("", "v", "verb", "Verb for workspace - create, remove, info", cxxopts::value(m_Verb), "<verb>");
 	m_Options.parse_positional({"verb"});
@@ -182,7 +182,7 @@ WorkspaceCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 		{
 			if (!m_HostName.empty())
 			{
-				HttpClient Http(m_HostName);
+				HttpClient Http = CreateHttpClient(m_HostName);
 				if (HttpClient::Response Result = Http.Get("/ws/refresh"); !Result)
 				{
 					ZEN_CONSOLE_WARN("Failed to refresh workspaces for host {}. Reason: '{}'", m_HostName, Result.ErrorMessage(""sv));
@@ -254,7 +254,7 @@ WorkspaceCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 		{
 			if (!m_HostName.empty())
 			{
-				HttpClient Http(m_HostName);
+				HttpClient Http = CreateHttpClient(m_HostName);
 				if (HttpClient::Response Result = Http.Get("/ws/refresh"); !Result)
 				{
 					ZEN_CONSOLE_WARN("Failed to refresh workspaces for host {}. Reason: '{}'", m_HostName, Result.ErrorMessage(""sv));
@@ -275,7 +275,7 @@ WorkspaceCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 WorkspaceShareCommand::WorkspaceShareCommand()
 {
 	m_Options.add_options()("h,help", "Print help");
-	m_Options.add_option("", "u", "hosturl", "Host URL", cxxopts::value(m_HostName)->default_value(""), "<hosturl>");
+	m_Options.add_option("", "u", "hosturl", kHostUrlHelp, cxxopts::value(m_HostName)->default_value(""), "<hosturl>");
 	m_Options.add_options()("system-dir", "Specify system root", cxxopts::value(m_SystemRootDir));
 	m_Options.add_option("", "v", "verb", "Verb for workspace - create, remove, info", cxxopts::value(m_Verb), "<verb>");
 	m_Options.parse_positional({"verb"});
@@ -475,7 +475,7 @@ WorkspaceShareCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char**
 		{
 			if (!m_HostName.empty())
 			{
-				HttpClient Http(m_HostName);
+				HttpClient Http = CreateHttpClient(m_HostName);
 				if (HttpClient::Response Result = Http.Get("/ws/refresh"); !Result)
 				{
 					ZEN_CONSOLE_WARN("Failed to refresh workspaces for host {}. Reason: '{}'", m_HostName, Result.ErrorMessage(""sv));
@@ -592,7 +592,7 @@ WorkspaceShareCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char**
 		{
 			if (!m_HostName.empty())
 			{
-				HttpClient Http(m_HostName);
+				HttpClient Http = CreateHttpClient(m_HostName);
 				if (HttpClient::Response Result = Http.Get("/ws/refresh"); !Result)
 				{
 					ZEN_CONSOLE_WARN("Failed to refresh workspaces for host {}. Reason: '{}'", m_HostName, Result.ErrorMessage(""sv));
@@ -645,7 +645,7 @@ WorkspaceShareCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char**
 			throw OptionParseException("Unable to resolve server specification", SubOption->help());
 		}
 
-		HttpClient Http(m_HostName);
+		HttpClient Http = CreateHttpClient(m_HostName);
 		if (HttpClient::Response Result = Http.Get(fmt::format("/ws/{}/files", GetShareIdentityUrl(m_FilesOptions)), {}, Params))
 		{
 			ZEN_CONSOLE("{}: {}", Result, Result.ToText());
@@ -678,7 +678,7 @@ WorkspaceShareCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char**
 			throw OptionParseException("Unable to resolve server specification", SubOption->help());
 		}
 
-		HttpClient Http(m_HostName);
+		HttpClient Http = CreateHttpClient(m_HostName);
 		if (HttpClient::Response Result = Http.Get(fmt::format("/ws/{}/entries", GetShareIdentityUrl(m_EntriesOptions)), {}, Params))
 		{
 			ZEN_CONSOLE("{}: {}", Result, Result.ToText());
@@ -753,8 +753,8 @@ WorkspaceShareCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char**
 			throw OptionParseException("'--chunk' is required", SubOption->help());
 		}
 
-		HttpClient Http(m_HostName);
-		m_ChunkId = ChunksToOidStrings(Http, m_WorkspaceId, m_ShareId, std::vector<std::string>{m_ChunkId})[0];
+		HttpClient Http = CreateHttpClient(m_HostName);
+		m_ChunkId		= ChunksToOidStrings(Http, m_WorkspaceId, m_ShareId, std::vector<std::string>{m_ChunkId})[0];
 
 		HttpClient::KeyValueMap Params;
 		if (m_Offset != 0)
@@ -794,8 +794,8 @@ WorkspaceShareCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char**
 			throw OptionParseException("'--chunks' is required", SubOption->help());
 		}
 
-		HttpClient Http(m_HostName);
-		m_ChunkIds = ChunksToOidStrings(Http, m_WorkspaceId, m_ShareId, m_ChunkIds);
+		HttpClient Http = CreateHttpClient(m_HostName);
+		m_ChunkIds		= ChunksToOidStrings(Http, m_WorkspaceId, m_ShareId, m_ChunkIds);
 
 		std::vector<RequestChunkEntry> ChunkRequests;
 		ChunkRequests.resize(m_ChunkIds.size());