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, 2 insertions, 2 deletions

diff --git a/src/zen/cmds/version_cmd.cpp b/src/zen/cmds/version_cmd.cpp
index ed34d7011..0948de1bb 100644
--- a/src/zen/cmds/version_cmd.cpp
+++ b/src/zen/cmds/version_cmd.cpp
@@ -20,7 +20,7 @@ using namespace std::literals;
 VersionCommand::VersionCommand()
 {
 	m_Options.add_options()("h,help", "Print help");
-	m_Options.add_option("", "u", "hosturl", "Host URL", cxxopts::value(m_HostName), "[hosturl]");
+	m_Options.add_option("", "u", "hosturl", kHostUrlHelp, cxxopts::value(m_HostName), "[hosturl]");
 	m_Options.add_option("", "d", "detailed", "Detailed Version", cxxopts::value(m_DetailedVersion), "[detailedversion]");
 	m_Options.add_option("", "o", "output-path", "Path for output", cxxopts::value(m_OutputPath), "[outputpath]");
 	m_Options.parse_positional({"hosturl"});
@@ -57,7 +57,7 @@ VersionCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 			ZEN_CONSOLE("Querying host {}", m_HostName);
 		}
 
-		HttpClient Client(m_HostName, HttpClientSettings{.Timeout = std::chrono::milliseconds(5000)});
+		HttpClient Client = CreateHttpClient(m_HostName, {.Timeout = std::chrono::milliseconds(5000)});
 
 		HttpClient::KeyValueMap Parameters;
 		if (m_DetailedVersion)