Dashboard refresh (logs, storage, network, object store, docs) (#835)

## Summary

This PR adds a session management service, several new dashboard pages, and a number of infrastructure improvements.

### Sessions Service
- `SessionsServiceClient` in `zenutil` announces sessions to a remote zenserver with a 15s heartbeat (POST/PUT/DELETE lifecycle)
- Storage server registers itself with its own local sessions service on startup
- Session mode attribute coupled to server mode (Compute, Proxy, Hub, etc.)
- Ended sessions tracked with `ended_at` timestamp; status filtering (Active/Ended/All)
- `--sessions-url` config option for remote session announcement
- In-process log sink (`InProcSessionLogSink`) forwards server log output to the server's own session, visible in the dashboard

### Session Log Viewer
- POST/GET endpoints for session logs (`/sessions/{id}/log`) supporting raw text and structured JSON/CbObject with batch `entries` array
- In-memory log storage per session (capped at 10k entries) with cursor-based pagination for efficient incremental fetching
- Log panel in the sessions dashboard with incremental DOM updates, auto-scroll (Follow toggle), newest-first toggle, text filter, and log-level coloring
- Auto-selects the server's own session on page load

### TCP Log Streaming
- `LogStreamListener` and `TcpLogStreamSink` for log delivery over TCP
- Sequence numbers on each message with drop detection and synthetic "dropped" notice on gaps
- Gathered buffer writes to reduce syscall overhead when flushing batches
- Tests covering basic delivery, multi-line splitting, drop detection, and sequencing

### New Dashboard Pages
- **Sessions**: master-detail layout with selectable rows, metadata panel, live WebSocket updates, paging, abbreviated date formatting, and "this" pill for the local session
- **Object Store**: summary stats tiles and bucket table with click-to-expand inline object listing (`GET /obj/`)
- **Storage**: per-volume disk usage breakdown (`GET /admin/storage`), Garbage Collection status section (next-run countdown, last-run stats), and GC History table with paginated rows and expandable detail panels
- **Network**: overview tiles, per-service request table, proxy connections, and live WebSocket updates; distinct client IPs and session counts via HyperLogLog

### Documentation Page
- In-dashboard Docs page with sidebar navigation, markdown rendering (via `marked`), Mermaid diagram support (theme-aware), collapsible sections, text filtering with highlighting, and cross-document linking
- New user-facing docs: `overview.md` (with architecture and per-mode diagrams), `sessions.md`, `cache.md`, `projects.md`; updated `compute.md`
- Dev docs moved to `docs/dev/`

### Infrastructure & Bug Fixes
- **Deflate compression** for the embedded frontend zip (~3.4MB → ~950KB); zlib inflate support added to `ZipFs` with cached decompressed buffers
- **Local IP addresses**: `GetLocalIpAddresses()` (Windows via `GetAdaptersAddresses`, Linux/Mac via `getifaddrs`); surfaced in `/status/status`, `/health/info`, and the dashboard banner
- **Dashboard nav**: unified into `zen-nav` web component with `MutationObserver` for dynamically added links, CSS `::part()` to merge banner/nav border radii, and prefix-based active link detection
- Stats broadcast refactored from manual JSON string concatenation to `CbObjectWriter`; `CbObject`-to-JS conversion improved for `TimeSpan`, `DateTime`, and large integers
- Stats WebSocket boilerplate consolidated into `ZenPage.connect_stats_ws()`

6 files changed, 676 insertions, 97 deletions

diff --git a/src/zenutil/include/zenutil/sessionsclient.h b/src/zenutil/include/zenutil/sessionsclient.h
new file mode 100644
index 000000000..aca45e61d
--- /dev/null
+++ b/src/zenutil/include/zenutil/sessionsclient.h
@@ -0,0 +1,65 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/compactbinary.h>
+#include <zencore/logging.h>
+#include <zencore/logging/sink.h>
+
+#include <zencore/uid.h>
+
+#include <memory>
+#include <string>
+
+namespace zen {
+
+class HttpClient;
+
+/// Client for announcing and maintaining a session on a remote zenserver's /sessions/ endpoint.
+/// Follows the same best-effort pattern as ZenComputeServer's coordinator announce.
+class SessionsServiceClient
+{
+public:
+	struct Options
+	{
+		std::string TargetUrl;				// Base URL of the target zenserver (e.g. "http://localhost:8558")
+		std::string AppName;				// Application name to register
+		std::string Mode;					// Server mode (e.g. "Server", "Compute", "Proxy")
+		Oid			SessionId = Oid::Zero;	// Session ID to register under
+		Oid			JobId	  = Oid::Zero;	// Optional job ID
+	};
+
+	explicit SessionsServiceClient(Options Opts);
+	~SessionsServiceClient();
+
+	SessionsServiceClient(const SessionsServiceClient&) = delete;
+	SessionsServiceClient& operator=(const SessionsServiceClient&) = delete;
+
+	/// POST /sessions/{id} — register or re-announce the session with optional metadata.
+	[[nodiscard]] bool Announce(CbObjectView Metadata = {});
+
+	/// PUT /sessions/{id} — update metadata on an existing session.
+	[[nodiscard]] bool UpdateMetadata(CbObjectView Metadata = {});
+
+	/// DELETE /sessions/{id} — remove the session.
+	[[nodiscard]] bool Remove();
+
+	/// Create a logging sink that forwards log messages to the session's log endpoint.
+	/// The sink batches messages on a background thread and POSTs them periodically.
+	/// The returned sink can be added to any logger via Logger::AddSink().
+	logging::SinkPtr CreateLogSink();
+
+	const Options&	   GetOptions() const { return m_Options; }
+	const std::string& GetSessionPath() const { return m_SessionPath; }
+
+private:
+	CbObject BuildRequestBody(CbObjectView Metadata) const;
+
+	LoggerRef					Log() { return m_Log; }
+	LoggerRef					m_Log;
+	Options						m_Options;
+	std::string					m_SessionPath;	// "sessions/<hex>"
+	std::unique_ptr<HttpClient> m_Http;
+};
+
+}  // namespace zen
diff --git a/src/zenutil/include/zenutil/splitconsole/logstreamlistener.h b/src/zenutil/include/zenutil/splitconsole/logstreamlistener.h
index 06544308c..f3b960f51 100644
--- a/src/zenutil/include/zenutil/splitconsole/logstreamlistener.h
+++ b/src/zenutil/include/zenutil/splitconsole/logstreamlistener.h
@@ -6,7 +6,7 @@
 
 #include <cstdint>
 #include <memory>
-#include <string>
+#include <string_view>
 
 ZEN_THIRD_PARTY_INCLUDES_START
 #include <asio/io_context.hpp>
@@ -14,44 +14,37 @@ ZEN_THIRD_PARTY_INCLUDES_END
 
 namespace zen {
 
-/// Interface for receiving log lines from a LogStreamListener.
-/// Clients implement this to route received log messages to their desired output.
-class LogStreamHandler
+/// Abstract target for log lines received over a TCP log stream.
+class LogStreamTarget
 {
 public:
-	virtual ~LogStreamHandler() = default;
+	virtual ~LogStreamTarget() = default;
 
-	virtual void AppendLogLine(std::string Line) = 0;
+	/// Called (potentially from any thread) when a log line is received.
+	virtual void AppendLogLine(std::string_view Text) = 0;
 };
 
 /// TCP listener that accepts connections from remote processes streaming log messages.
 /// Each message is a CbObject with fields: "text" (string), "source" (string), "level" (string, optional).
 ///
-/// A LogStreamHandler can be set to receive parsed log lines. If no handler is set,
-/// received messages are silently discarded.
-///
 /// Two modes of operation:
-///  - Owned thread: pass only Port; an internal IO thread is created.
+///  - Owned thread: pass only Target and Port; an internal IO thread is created.
 ///  - External io_context: pass an existing asio::io_context; no thread is created,
 ///    the caller is responsible for running the io_context.
 class LogStreamListener
 {
 public:
 	/// Start listening with an internal IO thread.
-	explicit LogStreamListener(uint16_t Port = 0);
+	LogStreamListener(LogStreamTarget& Target, uint16_t Port = 0);
 
 	/// Start listening on an externally-driven io_context (no thread created).
-	LogStreamListener(asio::io_context& IoContext, uint16_t Port = 0);
+	LogStreamListener(LogStreamTarget& Target, asio::io_context& IoContext, uint16_t Port = 0);
 
 	~LogStreamListener();
 
 	LogStreamListener(const LogStreamListener&) = delete;
 	LogStreamListener& operator=(const LogStreamListener&) = delete;
 
-	/// Set the handler that will receive parsed log lines. May be called at any time.
-	/// Pass nullptr to stop delivering messages.
-	void SetHandler(LogStreamHandler* Handler);
-
 	/// Returns the actual port the listener is bound to.
 	uint16_t GetPort() const;
 
@@ -63,4 +56,6 @@ private:
 	std::unique_ptr<Impl> m_Impl;
 };
 
+void logstreamlistener_forcelink();
+
 }  // namespace zen
diff --git a/src/zenutil/include/zenutil/splitconsole/tcplogstreamsink.h b/src/zenutil/include/zenutil/splitconsole/tcplogstreamsink.h
index 2ab7d469e..f4ac5ff22 100644
--- a/src/zenutil/include/zenutil/splitconsole/tcplogstreamsink.h
+++ b/src/zenutil/include/zenutil/splitconsole/tcplogstreamsink.h
@@ -3,11 +3,11 @@
 #pragma once
 
 #include <zencore/compactbinarybuilder.h>
-#include <zencore/logging.h>
 #include <zencore/logging/sink.h>
 #include <zencore/thread.h>
 
 ZEN_THIRD_PARTY_INCLUDES_START
+#include <EASTL/fixed_vector.h>
 #include <asio.hpp>
 ZEN_THIRD_PARTY_INCLUDES_END
 
@@ -17,6 +17,7 @@ ZEN_THIRD_PARTY_INCLUDES_END
 #include <mutex>
 #include <string>
 #include <thread>
+#include <vector>
 
 namespace zen {
 
@@ -52,22 +53,7 @@ public:
 
 	void Log(const logging::LogMessage& Msg) override
 	{
-		logging::MemoryBuffer Formatted;
-		{
-			RwLock::SharedLockScope Lock(m_FormatterLock);
-			if (m_Formatter)
-			{
-				m_Formatter->Format(Msg, Formatted);
-			}
-			else
-			{
-				// Fallback: use raw payload
-				auto Payload = Msg.GetPayload();
-				Formatted.append(Payload.data(), Payload.data() + Payload.size());
-			}
-		}
-
-		std::string_view Text(Formatted.data(), Formatted.size());
+		std::string_view Text = Msg.GetPayload();
 
 		// Strip trailing newlines
 		while (!Text.empty() && (Text.back() == '\n' || Text.back() == '\r'))
@@ -75,20 +61,22 @@ public:
 			Text.remove_suffix(1);
 		}
 
-		// Build CbObject with text, source, and level fields
+		uint64_t Seq = m_NextSequence.fetch_add(1, std::memory_order_relaxed);
+
+		// Build CbObject with text, source, level, and sequence number fields
 		CbObjectWriter Writer;
 		Writer.AddString("text", Text);
 		Writer.AddString("source", m_Source);
-		Writer.AddString("level", ToStringView(Msg.GetLevel()));
+		Writer.AddString("level", logging::ToStringView(Msg.GetLevel()));
+		Writer.AddInteger("seq", Seq);
 		CbObject Obj = Writer.Save();
 
 		// Enqueue for async write
 		{
 			std::lock_guard<std::mutex> Lock(m_QueueMutex);
-			if (m_Queue.size() >= m_MaxQueueSize)
+			while (m_Queue.size() >= m_MaxQueueSize)
 			{
 				m_Queue.pop_front();
-				m_DroppedMessages.fetch_add(1, std::memory_order_relaxed);
 			}
 			m_Queue.push_back(std::move(Obj));
 		}
@@ -100,10 +88,9 @@ public:
 		// Nothing to flush — writes happen asynchronously
 	}
 
-	void SetFormatter(std::unique_ptr<logging::Formatter> InFormatter) override
+	void SetFormatter(std::unique_ptr<logging::Formatter> /*InFormatter*/) override
 	{
-		RwLock::ExclusiveLockScope Lock(m_FormatterLock);
-		m_Formatter = std::move(InFormatter);
+		// Not used — we output the raw payload directly
 	}
 
 private:
@@ -131,13 +118,6 @@ private:
 				Batch.swap(m_Queue);
 			}
 
-			uint32_t Dropped = m_DroppedMessages.exchange(0, std::memory_order_relaxed);
-			if (Dropped > 0)
-			{
-				// We could/should log here, but that could cause a feedback loop which
-				// would trigger subsequent dropped message warnings
-			}
-
 			if (!m_Connected && !Connect())
 			{
 				if (m_Stopping)
@@ -147,16 +127,21 @@ private:
 				continue;  // drop batch — will retry on next batch
 			}
 
+			// Build a gathered buffer sequence so the entire batch is written
+			// in a single socket operation (or as few as the OS needs).
+			eastl::fixed_vector<asio::const_buffer, 64> Buffers;
+			Buffers.reserve(Batch.size());
 			for (auto& Obj : Batch)
 			{
-				MemoryView		 View = Obj.GetView();
-				asio::error_code Ec;
-				asio::write(m_Socket, asio::buffer(View.GetData(), View.GetSize()), Ec);
-				if (Ec)
-				{
-					m_Connected = false;
-					break;	// drop remaining messages in batch
-				}
+				MemoryView View = Obj.GetView();
+				Buffers.emplace_back(View.GetData(), View.GetSize());
+			}
+
+			asio::error_code Ec;
+			asio::write(m_Socket, Buffers, Ec);
+			if (Ec)
+			{
+				m_Connected = false;
 			}
 		}
 	}
@@ -191,15 +176,14 @@ private:
 	std::string m_Source;
 	uint32_t	m_MaxQueueSize;
 
-	// Formatter (protected by RwLock since Log is called from multiple threads)
-	RwLock								m_FormatterLock;
-	std::unique_ptr<logging::Formatter> m_Formatter;
+	// Sequence counter — incremented atomically by Log() callers.
+	// Gaps in the sequence seen by the receiver indicate dropped messages.
+	std::atomic<uint64_t> m_NextSequence{0};
 
 	// Queue shared between Log() callers and IO thread
 	std::mutex							  m_QueueMutex;
 	std::condition_variable				  m_QueueCv;
 	std::deque<CbObject>				  m_Queue;
-	std::atomic<uint32_t>				  m_DroppedMessages{0};
 	bool								  m_Stopping = false;
 	std::chrono::steady_clock::time_point m_DrainDeadline;
 
diff --git a/src/zenutil/sessionsclient.cpp b/src/zenutil/sessionsclient.cpp
new file mode 100644
index 000000000..c62cc4099
--- /dev/null
+++ b/src/zenutil/sessionsclient.cpp
@@ -0,0 +1,377 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenutil/sessionsclient.h>
+
+#include <zencore/blockingqueue.h>
+#include <zencore/compactbinarybuilder.h>
+#include <zencore/fmtutils.h>
+#include <zencore/iobuffer.h>
+#include <zencore/logging/logmsg.h>
+#include <zencore/thread.h>
+#include <zenhttp/httpclient.h>
+
+#include <thread>
+#include <vector>
+
+ZEN_THIRD_PARTY_INCLUDES_START
+#include <fmt/format.h>
+ZEN_THIRD_PARTY_INCLUDES_END
+
+namespace zen {
+
+//////////////////////////////////////////////////////////////////////////
+//
+// SessionLogSink — batching log sink that forwards to /sessions/{id}/log
+//
+
+static const char*
+LogLevelToString(logging::LogLevel Level)
+{
+	switch (Level)
+	{
+		case logging::Trace:
+			return "trace";
+		case logging::Debug:
+			return "debug";
+		case logging::Info:
+			return "info";
+		case logging::Warn:
+			return "warn";
+		case logging::Err:
+			return "error";
+		case logging::Critical:
+			return "critical";
+		default:
+			return "info";
+	}
+}
+
+struct BufferedLogEntry
+{
+	enum class Type : uint8_t
+	{
+		Log,
+		Flush,
+		Shutdown
+	};
+
+	Type		Type = Type::Log;
+	std::string Level;
+	std::string Message;
+};
+
+class SessionLogSink final : public logging::Sink
+{
+public:
+	SessionLogSink(std::string TargetUrl, std::string LogPath) : m_LogPath(std::move(LogPath))
+	{
+		HttpClientSettings Settings;
+		Settings.ConnectTimeout = std::chrono::milliseconds(3000);
+		m_Http					= std::make_unique<HttpClient>(std::move(TargetUrl), Settings);
+
+		SetLevel(logging::Info);
+
+		m_WorkerThread = std::thread([this]() {
+			zen::SetCurrentThreadName("SessionLog");
+			WorkerLoop();
+		});
+	}
+
+	~SessionLogSink() override
+	{
+		BufferedLogEntry ShutdownMsg;
+		ShutdownMsg.Type = BufferedLogEntry::Type::Shutdown;
+		m_Queue.Enqueue(std::move(ShutdownMsg));
+
+		if (m_WorkerThread.joinable())
+		{
+			m_WorkerThread.join();
+		}
+	}
+
+	void Log(const logging::LogMessage& Msg) override
+	{
+		BufferedLogEntry Entry;
+		Entry.Type	  = BufferedLogEntry::Type::Log;
+		Entry.Level	  = LogLevelToString(Msg.GetLevel());
+		Entry.Message = std::string(Msg.GetPayload());
+		m_Queue.Enqueue(std::move(Entry));
+	}
+
+	void Flush() override
+	{
+		// Best-effort: enqueue a flush marker so the worker sends any pending entries
+		BufferedLogEntry FlushMsg;
+		FlushMsg.Type = BufferedLogEntry::Type::Flush;
+		m_Queue.Enqueue(std::move(FlushMsg));
+	}
+
+	void SetFormatter(std::unique_ptr<logging::Formatter> /*InFormatter*/) override
+	{
+		// No formatting needed — we send raw message text
+	}
+
+private:
+	static constexpr size_t BatchSize = 50;
+
+	void WorkerLoop()
+	{
+		std::vector<BufferedLogEntry> Batch;
+		Batch.reserve(BatchSize);
+
+		BufferedLogEntry Msg;
+		while (m_Queue.WaitAndDequeue(Msg))
+		{
+			if (Msg.Type == BufferedLogEntry::Type::Shutdown)
+			{
+				// Drain remaining log entries
+				BufferedLogEntry Remaining;
+				while (m_Queue.WaitAndDequeue(Remaining))
+				{
+					if (Remaining.Type == BufferedLogEntry::Type::Log)
+					{
+						Batch.push_back(std::move(Remaining));
+					}
+				}
+				if (!Batch.empty())
+				{
+					SendBatch(Batch);
+				}
+				return;
+			}
+
+			if (Msg.Type == BufferedLogEntry::Type::Flush)
+			{
+				if (!Batch.empty())
+				{
+					SendBatch(Batch);
+					Batch.clear();
+				}
+				continue;
+			}
+
+			// Log entry
+			Batch.push_back(std::move(Msg));
+
+			if (Batch.size() >= BatchSize)
+			{
+				SendBatch(Batch);
+				Batch.clear();
+			}
+			else
+			{
+				// Drain any additional queued entries without blocking
+				while (Batch.size() < BatchSize && m_Queue.Size() > 0)
+				{
+					BufferedLogEntry Extra;
+					if (m_Queue.WaitAndDequeue(Extra))
+					{
+						if (Extra.Type == BufferedLogEntry::Type::Shutdown)
+						{
+							if (!Batch.empty())
+							{
+								SendBatch(Batch);
+							}
+							// Drain remaining
+							while (m_Queue.WaitAndDequeue(Extra))
+							{
+								if (Extra.Type == BufferedLogEntry::Type::Log)
+								{
+									Batch.push_back(std::move(Extra));
+								}
+							}
+							if (!Batch.empty())
+							{
+								SendBatch(Batch);
+							}
+							return;
+						}
+						if (Extra.Type == BufferedLogEntry::Type::Log)
+						{
+							Batch.push_back(std::move(Extra));
+						}
+						else if (Extra.Type == BufferedLogEntry::Type::Flush)
+						{
+							break;
+						}
+					}
+				}
+
+				if (!Batch.empty())
+				{
+					SendBatch(Batch);
+					Batch.clear();
+				}
+			}
+		}
+	}
+
+	void SendBatch(const std::vector<BufferedLogEntry>& Batch)
+	{
+		try
+		{
+			CbObjectWriter Writer;
+			Writer.BeginArray("entries");
+			for (const BufferedLogEntry& Entry : Batch)
+			{
+				Writer.BeginObject();
+				Writer << "level" << Entry.Level;
+				Writer << "message" << Entry.Message;
+				Writer.EndObject();
+			}
+			Writer.EndArray();
+
+			HttpClient::Response Result = m_Http->Post(m_LogPath, Writer.Save());
+			(void)Result;  // Best-effort
+		}
+		catch (const std::exception&)
+		{
+			// Best-effort — silently discard on failure
+		}
+	}
+
+	std::string						m_LogPath;
+	std::unique_ptr<HttpClient>		m_Http;
+	BlockingQueue<BufferedLogEntry> m_Queue;
+	std::thread						m_WorkerThread;
+};
+
+SessionsServiceClient::SessionsServiceClient(Options Opts)
+: m_Log(logging::Get("sessionsclient"))
+, m_Options(std::move(Opts))
+, m_SessionPath(fmt::format("sessions/{}", m_Options.SessionId))
+{
+	HttpClientSettings Settings;
+	Settings.ConnectTimeout = std::chrono::milliseconds(3000);
+	m_Http					= std::make_unique<HttpClient>(m_Options.TargetUrl, Settings);
+}
+
+SessionsServiceClient::~SessionsServiceClient() = default;
+
+CbObject
+SessionsServiceClient::BuildRequestBody(CbObjectView Metadata) const
+{
+	CbObjectWriter Writer;
+	Writer << "appname" << m_Options.AppName;
+	if (!m_Options.Mode.empty())
+	{
+		Writer << "mode" << m_Options.Mode;
+	}
+	if (m_Options.JobId != Oid::Zero)
+	{
+		Writer << "jobid" << m_Options.JobId;
+	}
+	if (Metadata.GetSize() > 0)
+	{
+		Writer.AddObject("metadata", Metadata);
+	}
+	return Writer.Save();
+}
+
+bool
+SessionsServiceClient::Announce(CbObjectView Metadata)
+{
+	try
+	{
+		CbObject Body = BuildRequestBody(Metadata);
+
+		HttpClient::Response Result = m_Http->Post(m_SessionPath, std::move(Body));
+
+		if (Result.Error)
+		{
+			ZEN_WARN("sessions announce failed for '{}': HTTP error {} - {}",
+					 m_Options.TargetUrl,
+					 static_cast<int>(Result.Error->ErrorCode),
+					 Result.Error->ErrorMessage);
+			return false;
+		}
+		if (!IsHttpOk(Result.StatusCode))
+		{
+			ZEN_WARN("sessions announce failed for '{}': HTTP status {}", m_Options.TargetUrl, static_cast<int>(Result.StatusCode));
+			return false;
+		}
+
+		ZEN_INFO("session announced to '{}'", m_Options.TargetUrl);
+		return true;
+	}
+	catch (const std::exception& Ex)
+	{
+		ZEN_WARN("sessions announce failed for '{}': {}", m_Options.TargetUrl, Ex.what());
+		return false;
+	}
+}
+
+bool
+SessionsServiceClient::UpdateMetadata(CbObjectView Metadata)
+{
+	try
+	{
+		CbObject Body = BuildRequestBody(Metadata);
+
+		MemoryView View	   = Body.GetView();
+		IoBuffer   Payload = IoBufferBuilder::MakeCloneFromMemory(View, ZenContentType::kCbObject);
+
+		HttpClient::Response Result = m_Http->Put(m_SessionPath, Payload);
+
+		if (Result.Error)
+		{
+			ZEN_WARN("sessions update failed for '{}': HTTP error {} - {}",
+					 m_Options.TargetUrl,
+					 static_cast<int>(Result.Error->ErrorCode),
+					 Result.Error->ErrorMessage);
+			return false;
+		}
+		if (!IsHttpOk(Result.StatusCode))
+		{
+			ZEN_WARN("sessions update failed for '{}': HTTP status {}", m_Options.TargetUrl, static_cast<int>(Result.StatusCode));
+			return false;
+		}
+
+		return true;
+	}
+	catch (const std::exception& Ex)
+	{
+		ZEN_WARN("sessions update failed for '{}': {}", m_Options.TargetUrl, Ex.what());
+		return false;
+	}
+}
+
+bool
+SessionsServiceClient::Remove()
+{
+	try
+	{
+		HttpClient::Response Result = m_Http->Delete(m_SessionPath);
+
+		if (Result.Error)
+		{
+			ZEN_WARN("sessions remove failed for '{}': HTTP error {} - {}",
+					 m_Options.TargetUrl,
+					 static_cast<int>(Result.Error->ErrorCode),
+					 Result.Error->ErrorMessage);
+			return false;
+		}
+		if (!IsHttpOk(Result.StatusCode))
+		{
+			ZEN_WARN("sessions remove failed for '{}': HTTP status {}", m_Options.TargetUrl, static_cast<int>(Result.StatusCode));
+			return false;
+		}
+
+		ZEN_INFO("session removed from '{}'", m_Options.TargetUrl);
+		return true;
+	}
+	catch (const std::exception& Ex)
+	{
+		ZEN_WARN("sessions remove failed for '{}': {}", m_Options.TargetUrl, Ex.what());
+		return false;
+	}
+}
+
+logging::SinkPtr
+SessionsServiceClient::CreateLogSink()
+{
+	std::string LogPath = m_SessionPath + "/log";
+	return Ref(new SessionLogSink(m_Options.TargetUrl, std::move(LogPath)));
+}
+
+}  // namespace zen
diff --git a/src/zenutil/splitconsole/logstreamlistener.cpp b/src/zenutil/splitconsole/logstreamlistener.cpp
index 9f1d1a02c..04718b543 100644
--- a/src/zenutil/splitconsole/logstreamlistener.cpp
+++ b/src/zenutil/splitconsole/logstreamlistener.cpp
@@ -2,6 +2,7 @@
 
 #include <zenutil/splitconsole/logstreamlistener.h>
 
+#include <zenbase/refcount.h>
 #include <zencore/compactbinary.h>
 #include <zencore/fmtutils.h>
 #include <zencore/logging.h>
@@ -11,7 +12,6 @@ ZEN_THIRD_PARTY_INCLUDES_START
 #include <asio.hpp>
 ZEN_THIRD_PARTY_INCLUDES_END
 
-#include <atomic>
 #include <vector>
 
 namespace zen {
@@ -19,21 +19,17 @@ namespace zen {
 //////////////////////////////////////////////////////////////////////////
 // LogStreamSession — reads CbObject-framed messages from a single TCP connection
 
-class LogStreamSession : public std::enable_shared_from_this<LogStreamSession>
+class LogStreamSession : public RefCounted
 {
 public:
-	LogStreamSession(asio::ip::tcp::socket Socket, std::atomic<LogStreamHandler*>& Handler)
-	: m_Socket(std::move(Socket))
-	, m_Handler(Handler)
-	{
-	}
+	LogStreamSession(asio::ip::tcp::socket Socket, LogStreamTarget& Target) : m_Socket(std::move(Socket)), m_Target(Target) {}
 
 	void Start() { DoRead(); }
 
 private:
 	void DoRead()
 	{
-		auto Self = shared_from_this();
+		Ref<LogStreamSession> Self(this);
 		m_Socket.async_read_some(asio::buffer(m_ReadBuf.data() + m_BufferUsed, m_ReadBuf.size() - m_BufferUsed),
 								 [Self](const asio::error_code& Ec, std::size_t BytesRead) {
 									 if (Ec)
@@ -71,8 +67,17 @@ private:
 			std::string_view Text	= Obj["text"].AsString();
 			std::string_view Source = Obj["source"].AsString();
 
+			// Check sequence number for gaps (dropped messages)
+			uint64_t Seq = Obj["seq"].AsUInt64();
+			if (Seq > m_NextExpectedSeq)
+			{
+				uint64_t Dropped = Seq - m_NextExpectedSeq;
+				m_Target.AppendLogLine(fmt::format("[{}] *** {} log message(s) dropped ***", Source.empty() ? "log" : Source, Dropped));
+			}
+			m_NextExpectedSeq = Seq + 1;
+
 			// Split multi-line messages into individual AppendLogLine calls so that
-			// each line gets its own row in the SplitConsole ring buffer.
+			// each line gets its own row in the target's log output.
 			while (!Text.empty())
 			{
 				std::string_view Line = Text;
@@ -98,17 +103,13 @@ private:
 					continue;
 				}
 
-				LogStreamHandler* Handler = m_Handler.load(std::memory_order_acquire);
-				if (Handler)
+				if (!Source.empty())
 				{
-					if (!Source.empty())
-					{
-						Handler->AppendLogLine(fmt::format("[{}] {}", Source, Line));
-					}
-					else
-					{
-						Handler->AppendLogLine(std::string(Line));
-					}
+					m_Target.AppendLogLine(fmt::format("[{}] {}", Source, Line));
+				}
+				else
+				{
+					m_Target.AppendLogLine(Line);
 				}
 			}
 
@@ -128,10 +129,11 @@ private:
 		}
 	}
 
-	asio::ip::tcp::socket			m_Socket;
-	std::atomic<LogStreamHandler*>& m_Handler;
-	std::array<uint8_t, 65536>		m_ReadBuf{};
-	std::size_t						m_BufferUsed = 0;
+	asio::ip::tcp::socket	   m_Socket;
+	LogStreamTarget&		   m_Target;
+	std::array<uint8_t, 65536> m_ReadBuf{};
+	std::size_t				   m_BufferUsed		 = 0;
+	uint64_t				   m_NextExpectedSeq = 0;
 };
 
 //////////////////////////////////////////////////////////////////////////
@@ -140,7 +142,10 @@ private:
 struct LogStreamListener::Impl
 {
 	// Owned io_context mode — creates and runs its own thread
-	explicit Impl(uint16_t Port) : m_OwnedIoContext(std::make_unique<asio::io_context>()), m_Acceptor(*m_OwnedIoContext)
+	Impl(LogStreamTarget& Target, uint16_t Port)
+	: m_Target(Target)
+	, m_OwnedIoContext(std::make_unique<asio::io_context>())
+	, m_Acceptor(*m_OwnedIoContext)
 	{
 		SetupAcceptor(Port);
 		m_IoThread = std::thread([this]() {
@@ -150,7 +155,10 @@ struct LogStreamListener::Impl
 	}
 
 	// External io_context mode — caller drives the io_context
-	Impl(asio::io_context& IoContext, uint16_t Port) : m_Acceptor(IoContext) { SetupAcceptor(Port); }
+	Impl(LogStreamTarget& Target, asio::io_context& IoContext, uint16_t Port) : m_Target(Target), m_Acceptor(IoContext)
+	{
+		SetupAcceptor(Port);
+	}
 
 	~Impl() { Shutdown(); }
 
@@ -177,11 +185,12 @@ struct LogStreamListener::Impl
 
 	uint16_t GetPort() const { return m_Port; }
 
-	void SetHandler(LogStreamHandler* Handler) { m_Handler.store(Handler, std::memory_order_release); }
-
 private:
 	void SetupAcceptor(uint16_t Port)
 	{
+		auto& IoCtx = m_OwnedIoContext ? *m_OwnedIoContext : m_Acceptor.get_executor().context();
+		ZEN_UNUSED(IoCtx);
+
 		// Try dual-stack IPv6 first (accepts both IPv4 and IPv6), fall back to IPv4-only
 		asio::error_code Ec;
 		m_Acceptor.open(asio::ip::tcp::v6(), Ec);
@@ -218,7 +227,7 @@ private:
 				return;	 // acceptor closed
 			}
 
-			auto Session = std::make_shared<LogStreamSession>(std::move(Socket), m_Handler);
+			Ref<LogStreamSession> Session(new LogStreamSession(std::move(Socket), m_Target));
 			Session->Start();
 
 			if (!m_Stopped.load())
@@ -228,7 +237,7 @@ private:
 		});
 	}
 
-	std::atomic<LogStreamHandler*>	  m_Handler{nullptr};
+	LogStreamTarget&				  m_Target;
 	std::unique_ptr<asio::io_context> m_OwnedIoContext;	 // null when using external io_context
 	asio::ip::tcp::acceptor			  m_Acceptor;
 	std::thread						  m_IoThread;
@@ -239,22 +248,17 @@ private:
 //////////////////////////////////////////////////////////////////////////
 // LogStreamListener
 
-LogStreamListener::LogStreamListener(uint16_t Port) : m_Impl(std::make_unique<Impl>(Port))
+LogStreamListener::LogStreamListener(LogStreamTarget& Target, uint16_t Port) : m_Impl(std::make_unique<Impl>(Target, Port))
 {
 }
 
-LogStreamListener::LogStreamListener(asio::io_context& IoContext, uint16_t Port) : m_Impl(std::make_unique<Impl>(IoContext, Port))
+LogStreamListener::LogStreamListener(LogStreamTarget& Target, asio::io_context& IoContext, uint16_t Port)
+: m_Impl(std::make_unique<Impl>(Target, IoContext, Port))
 {
 }
 
 LogStreamListener::~LogStreamListener() = default;
 
-void
-LogStreamListener::SetHandler(LogStreamHandler* Handler)
-{
-	m_Impl->SetHandler(Handler);
-}
-
 uint16_t
 LogStreamListener::GetPort() const
 {
@@ -268,3 +272,155 @@ LogStreamListener::Shutdown()
 }
 
 }  // namespace zen
+
+#if ZEN_WITH_TESTS
+
+#	include <zencore/testing.h>
+#	include <zenutil/splitconsole/tcplogstreamsink.h>
+
+namespace zen {
+
+void
+logstreamlistener_forcelink()
+{
+}
+
+namespace {
+
+	class CollectingTarget : public LogStreamTarget
+	{
+	public:
+		void AppendLogLine(std::string_view Text) override
+		{
+			std::lock_guard<std::mutex> Lock(m_Mutex);
+			m_Lines.emplace_back(Text);
+			m_Cv.notify_all();
+		}
+
+		std::vector<std::string> WaitForLines(size_t Count, std::chrono::milliseconds Timeout = std::chrono::milliseconds(5000))
+		{
+			std::unique_lock<std::mutex> Lock(m_Mutex);
+			m_Cv.wait_for(Lock, Timeout, [&]() { return m_Lines.size() >= Count; });
+			return m_Lines;
+		}
+
+	private:
+		std::mutex				 m_Mutex;
+		std::condition_variable	 m_Cv;
+		std::vector<std::string> m_Lines;
+	};
+
+	logging::LogMessage MakeLogMessage(std::string_view Text, logging::LogLevel Level = logging::Info)
+	{
+		static logging::LogPoint Point{{}, Level, {}};
+		Point.Level = Level;
+		return logging::LogMessage(Point, "test", Text);
+	}
+
+}  // namespace
+
+TEST_SUITE_BEGIN("util.logstreamlistener");
+
+TEST_CASE("BasicMessageDelivery")
+{
+	CollectingTarget  Target;
+	LogStreamListener Listener(Target);
+
+	{
+		TcpLogStreamSink Sink("127.0.0.1", Listener.GetPort(), "TestSource", 64);
+		Sink.Log(MakeLogMessage("hello world"));
+		Sink.Log(MakeLogMessage("second line"));
+	}
+
+	auto Lines = Target.WaitForLines(2);
+	REQUIRE(Lines.size() == 2);
+	CHECK(Lines[0] == "[TestSource] hello world");
+	CHECK(Lines[1] == "[TestSource] second line");
+}
+
+TEST_CASE("MultiLineMessageSplit")
+{
+	CollectingTarget  Target;
+	LogStreamListener Listener(Target);
+
+	{
+		TcpLogStreamSink Sink("127.0.0.1", Listener.GetPort(), "src", 64);
+		Sink.Log(MakeLogMessage("line1\nline2\nline3"));
+	}
+
+	auto Lines = Target.WaitForLines(3);
+	REQUIRE(Lines.size() == 3);
+	CHECK(Lines[0] == "[src] line1");
+	CHECK(Lines[1] == "[src] line2");
+	CHECK(Lines[2] == "[src] line3");
+}
+
+TEST_CASE("DroppedMessageDetection")
+{
+	// Test sequence-gap detection deterministically by sending raw CbObjects
+	// with an explicit gap in sequence numbers, bypassing TcpLogStreamSink.
+	CollectingTarget  Target;
+	LogStreamListener Listener(Target);
+
+	{
+		asio::io_context	  IoContext;
+		asio::ip::tcp::socket Socket(IoContext);
+		Socket.connect(asio::ip::tcp::endpoint(asio::ip::make_address("127.0.0.1"), Listener.GetPort()));
+
+		// Send seq=0, then seq=5 — the listener should detect a gap of 4
+		for (uint64_t Seq : {uint64_t(0), uint64_t(5)})
+		{
+			CbObjectWriter Writer;
+			Writer.AddString("text", fmt::format("msg{}", Seq));
+			Writer.AddString("source", "src");
+			Writer.AddInteger("seq", Seq);
+			CbObject   Obj	= Writer.Save();
+			MemoryView View = Obj.GetView();
+
+			asio::write(Socket, asio::buffer(View.GetData(), View.GetSize()));
+		}
+	}
+
+	// Expect: msg0, drop notice, msg5
+	auto Lines = Target.WaitForLines(3);
+	REQUIRE(Lines.size() >= 3);
+	CHECK(Lines[0] == "[src] msg0");
+	CHECK(Lines[1].find("4 log message(s) dropped") != std::string::npos);
+	CHECK(Lines[2] == "[src] msg5");
+}
+
+TEST_CASE("SequenceNumbersAreContiguous")
+{
+	CollectingTarget  Target;
+	LogStreamListener Listener(Target);
+
+	constexpr int NumMessages = 5;
+	{
+		TcpLogStreamSink Sink("127.0.0.1", Listener.GetPort(), "seq", 64);
+		for (int i = 0; i < NumMessages; i++)
+		{
+			Sink.Log(MakeLogMessage(fmt::format("msg{}", i)));
+		}
+	}
+
+	auto Lines = Target.WaitForLines(NumMessages);
+	REQUIRE(Lines.size() == NumMessages);
+
+	// No "dropped" notices should appear when nothing is dropped
+	for (auto& Line : Lines)
+	{
+		CHECK(Line.find("dropped") == std::string::npos);
+	}
+
+	// Verify ordering
+	for (int i = 0; i < NumMessages; i++)
+	{
+		CHECK(Lines[i] == fmt::format("[seq] msg{}", i));
+	}
+}
+
+TEST_SUITE_END();
+
+}  // namespace zen
+
+#endif
diff --git a/src/zenutil/zenutil.cpp b/src/zenutil/zenutil.cpp
index 734813b69..c4d01554d 100644
--- a/src/zenutil/zenutil.cpp
+++ b/src/zenutil/zenutil.cpp
@@ -7,8 +7,9 @@
 #	include <zenutil/cloud/imdscredentials.h>
 #	include <zenutil/cloud/s3client.h>
 #	include <zenutil/cloud/sigv4.h>
-#	include <zenutil/rpcrecording.h>
 #	include <zenutil/config/commandlineoptions.h>
+#	include <zenutil/rpcrecording.h>
+#	include <zenutil/splitconsole/logstreamlistener.h>
 #	include <zenutil/wildcard.h>
 
 namespace zen {
@@ -19,6 +20,7 @@ zenutil_forcelinktests()
 	cache::rpcrecord_forcelink();
 	commandlineoptions_forcelink();
 	imdscredentials_forcelink();
+	logstreamlistener_forcelink();
 	s3client_forcelink();
 	sigv4_forcelink();
 	wildcard_forcelink();