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/JsonRpcTransport.h

@@ -1,11 +1,12 @@
 /*
- * JsonRpcTransport.h - placeholder transport for JSON-RPC over stdio (stub)
+ * JsonRpcTransport.h - minimal JSON-RPC over stdio transport
  */
 #ifndef KTE_JSON_RPC_TRANSPORT_H
 #define KTE_JSON_RPC_TRANSPORT_H
 
 #include <optional>
 #include <string>
+#include <mutex>
 
 namespace kte::lsp {
 struct JsonRpcMessage {
@@ -18,11 +19,24 @@ public:
 
 	~JsonRpcTransport() = default;
 
-	// Send a method call (request or notification) - stub does nothing
+	// Connect this transport to file descriptors (read from inFd, write to outFd)
+	void connect(int inFd, int outFd);
+
+	// Send a method call (request or notification)
+	// 'payload' should be a complete JSON object string to send as the message body.
 	void send(const std::string &method, const std::string &payload);
 
-	// Blocking read next message (stub => returns nullopt)
+	// Blocking read next message; returns nullopt on EOF or error
 	std::optional<JsonRpcMessage> read();
+
+private:
+	int inFd_  = -1;
+	int outFd_ = -1;
+	std::mutex writeMutex_;
+
+	// Limits to keep the transport resilient
+	static constexpr size_t kMaxHeaderLine = 16 * 1024; // 16 KiB per header line
+	static constexpr size_t kMaxBody       = 64ull * 1024ull * 1024ull; // 64 MiB body cap
 };
 } // namespace kte::lsp