Dashboard overhaul, compute integration (#814)

- **Frontend dashboard overhaul**: Unified compute/main dashboards into a single shared UI. Added new pages for cache, projects, metrics, sessions, info (build/runtime config, system stats). Added live-update via WebSockets with pause control, sortable detail tables, themed styling. Refactored compute/hub/orchestrator pages into modular JS.
- **HTTP server fixes and stats**: Fixed http.sys local-only fallback when default port is in use, implemented root endpoint redirect for http.sys, fixed Linux/Mac port reuse. Added /stats endpoint exposing HTTP server metrics (bytes transferred, request rates). Added WebSocket stats tracking.
- **OTEL/diagnostics hardening**: Improved OTLP HTTP exporter with better error handling and resilience. Extended diagnostics services configuration.
- **Session management**: Added new sessions service with HTTP endpoints for registering, updating, querying, and removing sessions. Includes session log file support. This is still WIP.
- **CLI subcommand support**: Added support for commands with subcommands in the zen CLI tool, with improved command dispatch.
- **Misc**: Exposed CPU usage/hostname to frontend, fixed JS compact binary float32/float64 decoding, limited projects displayed on front page to 25 sorted by last access, added vscode:// link support.

Also contains some fixes from TSAN analysis.

3 files changed, 115 insertions, 14 deletions

diff --git a/src/zenhttp/include/zenhttp/httpclient.h b/src/zenhttp/include/zenhttp/httpclient.h
index bec4984db..1bb36a298 100644
--- a/src/zenhttp/include/zenhttp/httpclient.h
+++ b/src/zenhttp/include/zenhttp/httpclient.h
@@ -118,6 +118,15 @@ private:
 
 class HttpClientBase;
 
+/** HTTP Client
+ *
+ * This is safe for use on multiple threads simultaneously, as each
+ * instance maintains an internal connection pool and will synchronize
+ * access to it as needed.
+ *
+ * Uses libcurl under the hood. We currently only use HTTP 1.1 features.
+ *
+ */
 class HttpClient
 {
 public:
diff --git a/src/zenhttp/include/zenhttp/httpserver.h b/src/zenhttp/include/zenhttp/httpserver.h
index c1152dc3e..0e1714669 100644
--- a/src/zenhttp/include/zenhttp/httpserver.h
+++ b/src/zenhttp/include/zenhttp/httpserver.h
@@ -13,6 +13,8 @@
 #include <zencore/uid.h>
 #include <zenhttp/httpcommon.h>
 
+#include <zentelemetry/stats.h>
+
 #include <functional>
 #include <gsl/gsl-lite.hpp>
 #include <list>
@@ -203,12 +205,34 @@ private:
 	int m_UriPrefixLength = 0;
 };
 
+struct IHttpStatsProvider
+{
+	/** Handle an HTTP stats request, writing the response directly.
+	 *  Implementations may inspect query parameters on the request
+	 *  to include optional detailed breakdowns.
+	 */
+	virtual void HandleStatsRequest(HttpServerRequest& Request) = 0;
+
+	/** Return the provider's current stats as a CbObject snapshot.
+	 *  Used by the WebSocket push thread to broadcast live updates
+	 *  without requiring an HttpServerRequest.  Providers that do
+	 *  not override this will be skipped in WebSocket broadcasts.
+	 */
+	virtual CbObject CollectStats() { return {}; }
+};
+
+struct IHttpStatsService
+{
+	virtual void RegisterHandler(std::string_view Id, IHttpStatsProvider& Provider)	  = 0;
+	virtual void UnregisterHandler(std::string_view Id, IHttpStatsProvider& Provider) = 0;
+};
+
 /** HTTP server
  *
  *	Implements the main event loop to service HTTP requests, and handles routing
  *  requests to the appropriate handler as registered via RegisterService
  */
-class HttpServer : public RefCounted
+class HttpServer : public RefCounted, public IHttpStatsProvider
 {
 public:
 	void RegisterService(HttpService& Service);
@@ -235,10 +259,46 @@ public:
 	virtual uint64_t GetTotalBytesReceived() const { return 0; }
 	virtual uint64_t GetTotalBytesSent() const { return 0; }
 
+	/** Mark that a request has been handled. Called by server implementations. */
+	void MarkRequest() { m_RequestMeter.Mark(); }
+
+	/** Set a default redirect path for root requests */
+	void SetDefaultRedirect(std::string_view Path) { m_DefaultRedirect = Path; }
+
+	std::string_view GetDefaultRedirect() const { return m_DefaultRedirect; }
+
+	/** Track active WebSocket connections — called by server implementations on upgrade/close. */
+	void	 OnWebSocketConnectionOpened() { m_ActiveWebSocketConnections.fetch_add(1, std::memory_order_relaxed); }
+	void	 OnWebSocketConnectionClosed() { m_ActiveWebSocketConnections.fetch_sub(1, std::memory_order_relaxed); }
+	uint64_t GetActiveWebSocketConnectionCount() const { return m_ActiveWebSocketConnections.load(std::memory_order_relaxed); }
+
+	/** Track WebSocket frame and byte counters — called by WS connection implementations per frame. */
+	void OnWebSocketFrameReceived(uint64_t Bytes)
+	{
+		m_WsFramesReceived.fetch_add(1, std::memory_order_relaxed);
+		m_WsBytesReceived.fetch_add(Bytes, std::memory_order_relaxed);
+	}
+	void OnWebSocketFrameSent(uint64_t Bytes)
+	{
+		m_WsFramesSent.fetch_add(1, std::memory_order_relaxed);
+		m_WsBytesSent.fetch_add(Bytes, std::memory_order_relaxed);
+	}
+
+	// IHttpStatsProvider
+	virtual CbObject CollectStats() override;
+	virtual void	 HandleStatsRequest(HttpServerRequest& Request) override;
+
 private:
 	std::vector<HttpService*> m_KnownServices;
 	int						  m_EffectivePort = 0;
 	std::string				  m_ExternalHost;
+	metrics::Meter			  m_RequestMeter;
+	std::string				  m_DefaultRedirect;
+	std::atomic<uint64_t>	  m_ActiveWebSocketConnections{0};
+	std::atomic<uint64_t>	  m_WsFramesReceived{0};
+	std::atomic<uint64_t>	  m_WsFramesSent{0};
+	std::atomic<uint64_t>	  m_WsBytesReceived{0};
+	std::atomic<uint64_t>	  m_WsBytesSent{0};
 
 	virtual void OnRegisterService(HttpService& Service)				   = 0;
 	virtual int	 OnInitialize(int BasePort, std::filesystem::path DataDir) = 0;
@@ -456,17 +516,6 @@ private:
 
 bool HandlePackageOffers(HttpService& Service, HttpServerRequest& Request, Ref<IHttpPackageHandler>& PackageHandlerRef);
 
-struct IHttpStatsProvider
-{
-	virtual void HandleStatsRequest(HttpServerRequest& Request) = 0;
-};
-
-struct IHttpStatsService
-{
-	virtual void RegisterHandler(std::string_view Id, IHttpStatsProvider& Provider)	  = 0;
-	virtual void UnregisterHandler(std::string_view Id, IHttpStatsProvider& Provider) = 0;
-};
-
 void http_forcelink();		 // internal
 void websocket_forcelink();	 // internal
 
diff --git a/src/zenhttp/include/zenhttp/httpstats.h b/src/zenhttp/include/zenhttp/httpstats.h
index e6fea6765..460315faf 100644
--- a/src/zenhttp/include/zenhttp/httpstats.h
+++ b/src/zenhttp/include/zenhttp/httpstats.h
@@ -3,23 +3,50 @@
 #pragma once
 
 #include <zencore/logging.h>
+#include <zencore/thread.h>
 #include <zenhttp/httpserver.h>
+#include <zenhttp/websocket.h>
 
+#include <atomic>
 #include <map>
+#include <memory>
+#include <thread>
+#include <vector>
+
+ZEN_THIRD_PARTY_INCLUDES_START
+#include <asio/io_context.hpp>
+#include <asio/steady_timer.hpp>
+ZEN_THIRD_PARTY_INCLUDES_END
 
 namespace zen {
 
-class HttpStatsService : public HttpService, public IHttpStatsService
+class HttpStatsService : public HttpService, public IHttpStatsService, public IWebSocketHandler
 {
 public:
-	HttpStatsService();
+	/// Construct without an io_context — optionally uses a dedicated push thread
+	/// for WebSocket stats broadcasting.
+	explicit HttpStatsService(bool EnableWebSockets = false);
+
+	/// Construct with an external io_context — uses an asio timer instead
+	/// of a dedicated thread for WebSocket stats broadcasting.
+	/// The caller must ensure the io_context outlives this service and that
+	/// its run loop is active.
+	HttpStatsService(asio::io_context& IoContext, bool EnableWebSockets = true);
+
 	~HttpStatsService();
 
+	void Shutdown();
+
 	virtual const char* BaseUri() const override;
 	virtual void		HandleRequest(HttpServerRequest& Request) override;
 	virtual void		RegisterHandler(std::string_view Id, IHttpStatsProvider& Provider) override;
 	virtual void		UnregisterHandler(std::string_view Id, IHttpStatsProvider& Provider) override;
 
+	// IWebSocketHandler
+	void OnWebSocketOpen(Ref<WebSocketConnection> Connection) override;
+	void OnWebSocketMessage(WebSocketConnection& Conn, const WebSocketMessage& Msg) override;
+	void OnWebSocketClose(WebSocketConnection& Conn, uint16_t Code, std::string_view Reason) override;
+
 private:
 	LoggerRef		  m_Log;
 	HttpRequestRouter m_Router;
@@ -28,6 +55,22 @@ private:
 
 	RwLock									   m_Lock;
 	std::map<std::string, IHttpStatsProvider*> m_Providers;
+
+	// WebSocket push
+	RwLock								  m_WsConnectionsLock;
+	std::vector<Ref<WebSocketConnection>> m_WsConnections;
+	std::atomic<bool>					  m_PushEnabled{false};
+
+	void BroadcastStats();
+
+	// Thread-based push (when no io_context is provided)
+	std::thread m_PushThread;
+	Event		m_PushEvent;
+	void		PushThreadFunction();
+
+	// Timer-based push (when an io_context is provided)
+	std::unique_ptr<asio::steady_timer> m_PushTimer;
+	void								EnqueuePushTimer();
 };
 
 }  // namespace zen