Add SQL, Erlang, and Forth highlighter implementations and tests for LSP process and transport handling.

- Added highlighters for new languages (SQL, Erlang, Forth) with filetype recognition.
- Updated and reorganized syntax files to maintain consistency and modularity.
- Introduced LSP transport framing unit tests and JSON decoding/dispatch tests.
- Refactored `LspManager`, integrating UTF-16/UTF-8 position conversions and robust diagnostics handling.
- Enhanced server start/restart logic with workspace root detection and logging to improve LSP usability.

lsp/LspProcessClient.h

@@ -7,6 +7,15 @@
 #include <memory>
 #include <string>
 #include <vector>
+#include <thread>
+#include <atomic>
+#include <functional>
+#include <unordered_map>
+#include <mutex>
+#include <chrono>
+#include <list>
+
+#include "json.h"
 
 #include "LspClient.h"
 #include "JsonRpcTransport.h"
@@ -32,15 +41,148 @@ public:
 
 	void didSave(const std::string &uri) override;
 
+	// Language Features (wire-up via dispatcher; minimal callbacks for now)
+	void completion(const std::string &uri, Position pos,
+	                CompletionCallback cb) override;
+
+	void hover(const std::string &uri, Position pos,
+	           HoverCallback cb) override;
+
+	void definition(const std::string &uri, Position pos,
+	                LocationCallback cb) override;
+
 	bool isRunning() const override;
 
 	std::string getServerName() const override;
 
+
+	void setDiagnosticsHandler(DiagnosticsHandler h) override
+	{
+		diagnosticsHandler_ = std::move(h);
+	}
+
 private:
 	std::string command_;
 	std::vector<std::string> args_;
 	std::unique_ptr<JsonRpcTransport> transport_;
-	bool running_ = false;
+	bool running_         = false;
+	bool debug_           = false;
+	int inFd_             = -1; // read from server (server stdout)
+	int outFd_            = -1; // write to server (server stdin)
+	pid_t childPid_       = -1;
+	int nextRequestIntId_ = 1;
+	std::string pendingInitializeId_{}; // echo exactly as sent (string form)
+
+	// Incoming processing
+	std::thread reader_;
+	std::atomic<bool> stopReader_{false};
+	DiagnosticsHandler diagnosticsHandler_{};
+
+	// Simple request dispatcher: map request id -> callback
+	struct PendingRequest {
+		std::string method;
+		// If error is present, errorJson points to it; otherwise nullptr
+		std::function<void(const nlohmann::json & result, const nlohmann::json * errorJson)> callback;
+		// Optional timeout
+		std::chrono::steady_clock::time_point deadline{}; // epoch if no timeout
+		// Order tracking for LRU eviction
+		std::list<std::string>::iterator orderIt{};
+	};
+
+	std::unordered_map<std::string, PendingRequest> pending_;
+	// Maintain insertion order (oldest at front)
+	std::list<std::string> pendingOrder_;
+	std::mutex pendingMutex_;
+
+	// Timeout/watchdog for pending requests
+	std::thread timeoutThread_;
+	std::atomic<bool> stopTimeout_{false};
+	int64_t requestTimeoutMs_ = 0; // 0 = disabled
+	size_t maxPending_        = 0; // 0 = unlimited
+
+	bool spawnServerProcess();
+
+	void terminateProcess();
+
+	static std::string toFileUri(const std::string &path);
+
+	void sendInitialize(const std::string &rootPath);
+
+	void startReader();
+
+	void stopReader();
+
+	void readerLoop();
+
+	void handleIncoming(const std::string &json);
+
+	// Helper to send a request with params and register a response callback
+	int sendRequest(const std::string &method, const nlohmann::json &params,
+	                std::function<void(const nlohmann::json & result, const nlohmann::json * errorJson)> cb);
+
+	// Start/stop timeout thread
+	void startTimeoutWatchdog();
+
+	void stopTimeoutWatchdog();
+
+public:
+	// Test hook: inject a raw JSON message as if received from server
+	void debugInjectMessageForTest(const std::string &raw)
+	{
+		handleIncoming(raw);
+	}
+
+
+	// Test hook: add a pending request entry manually
+	void debugAddPendingForTest(const std::string &id, const std::string &method,
+	                            std::function<void(const nlohmann::json & result,
+	                            const nlohmann::json *errorJson)
+
+	>
+	cb
+	)
+	{
+		std::lock_guard<std::mutex> lk(pendingMutex_);
+		pendingOrder_.push_back(id);
+		auto it = pendingOrder_.end();
+		--it;
+		PendingRequest pr{method, std::move(cb), {}, it};
+		pending_[id] = std::move(pr);
+	}
+
+
+	// Test hook: override timeout
+	void setRequestTimeoutMsForTest(int64_t ms)
+	{
+		requestTimeoutMs_ = ms;
+	}
+
+
+	// Test hook: set max pending
+	void setMaxPendingForTest(size_t maxPending)
+	{
+		maxPending_ = maxPending;
+	}
+
+
+	// Test hook: set running flag (to allow sendRequest in tests without spawning)
+	void setRunningForTest(bool r)
+	{
+		running_ = r;
+	}
+
+
+	// Test hook: send a raw request using internal machinery
+	int debugSendRequestForTest(const std::string &method, const nlohmann::json &params,
+	                            std::function<void(const nlohmann::json & result,
+	                            const nlohmann::json *errorJson)
+
+	>
+	cb
+	)
+	{
+		return sendRequest(method, params, std::move(cb));
+	}
 };
 } // namespace kte::lsp