Add extensive debugging to callTool and send methods

Added NSLog tracing throughout callTool() and send() to identify
exact hang point in tool execution flow.

Debugging points:
- callTool() entry/exit
- send() entry and continuation flow
- Task creation inside continuation
- addPendingRequest() call
- connection.send() call and result

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: dcherrera

Sources/MCP/Client/Client.swift

@@ -319,27 +319,34 @@ public actor Client {
 
     /// Send a request and receive its response
     public func send<M: Method>(_ request: Request<M>) async throws -> M.Result {
+        NSLog("🔵 CLIENT.send() ENTRY - method: \(M.method), id: \(request.id)")
         guard let connection = connection else {
             throw MCPError.internalError("Client connection not initialized")
         }
 
         let requestData = try encoder.encode(request)
+        NSLog("🔵 CLIENT.send() - Encoded request, entering continuation")
 
         // Store the pending request first
         return try await withCheckedThrowingContinuation { continuation in
+            NSLog("🔵 CLIENT.send() - Inside continuation, creating Task")
             Task {
+                NSLog("🔵 CLIENT.send() - Task started, adding pending request")
                 // Add the pending request before attempting to send
                 self.addPendingRequest(
                     id: request.id,
                     continuation: continuation,
                     type: M.Result.self
                 )
+                NSLog("🔵 CLIENT.send() - Pending request added, calling connection.send()")
 
                 // Send the request data
                 do {
                     // Use the existing connection send
                     try await connection.send(requestData)
+                    NSLog("🔵 CLIENT.send() - connection.send() succeeded")
                 } catch {
+                    NSLog("🔵 CLIENT.send() - connection.send() failed: \(error)")
                     // If send fails, try to remove the pending request.
                     // Resume with the send error only if we successfully removed the request,
                     // indicating the response handler hasn't processed it yet.
@@ -642,9 +649,13 @@ public actor Client {
     public func callTool(name: String, arguments: [String: Value]? = nil) async throws -> (
         content: [Tool.Content], isError: Bool?
     ) {
+        NSLog("🔵 CLIENT.callTool() ENTRY - tool: \(name)")
         try validateServerCapability(\.tools, "Tools")
+        NSLog("🔵 CLIENT.callTool() - Creating request")
         let request = CallTool.request(.init(name: name, arguments: arguments))
+        NSLog("🔵 CLIENT.callTool() - Calling send()")
         let result = try await send(request)
+        NSLog("🔵 CLIENT.callTool() - send() RETURNED!")
         return (content: result.content, isError: result.isError)
     }