Rename the example file names related to SSE.

This PR renamed the files related to the SSE example and fixed the README.md.
Because missing files were specified in README.md.

And also, I removed the word 'test' from the file names related to the SSE example.
Other examples file names do not contain the word `test`.

examples/streamable_http_client.rb

@@ -0,0 +1,207 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "net/http"
+require "uri"
+require "json"
+require "logger"
+
+# Logger for client operations
+logger = Logger.new($stdout)
+logger.formatter = proc do |severity, datetime, _progname, msg|
+  "[CLIENT] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n"
+end
+
+# Server configuration
+SERVER_URL = "http://localhost:9393/mcp"
+PROTOCOL_VERSION = "2024-11-05"
+
+# Helper method to make JSON-RPC requests
+def make_request(session_id, method, params = {}, id = nil)
+  uri = URI(SERVER_URL)
+  http = Net::HTTP.new(uri.host, uri.port)
+
+  request = Net::HTTP::Post.new(uri)
+  request["Content-Type"] = "application/json"
+  request["Mcp-Session-Id"] = session_id if session_id
+
+  body = {
+    jsonrpc: "2.0",
+    method: method,
+    params: params,
+    id: id || SecureRandom.uuid,
+  }
+
+  request.body = body.to_json
+  response = http.request(request)
+
+  {
+    status: response.code,
+    headers: response.to_hash,
+    body: JSON.parse(response.body),
+  }
+rescue => e
+  { error: e.message }
+end
+
+# Connect to SSE stream
+def connect_sse(session_id, logger)
+  uri = URI(SERVER_URL)
+
+  logger.info("Connecting to SSE stream...")
+
+  Net::HTTP.start(uri.host, uri.port) do |http|
+    request = Net::HTTP::Get.new(uri)
+    request["Mcp-Session-Id"] = session_id
+    request["Accept"] = "text/event-stream"
+    request["Cache-Control"] = "no-cache"
+
+    http.request(request) do |response|
+      if response.code == "200"
+        logger.info("SSE stream connected successfully")
+
+        response.read_body do |chunk|
+          chunk.split("\n").each do |line|
+            if line.start_with?("data: ")
+              data = line[6..-1]
+              begin
+                logger.info("SSE data: #{data}")
+              rescue JSON::ParserError
+                logger.debug("Non-JSON SSE data: #{data}")
+              end
+            elsif line.start_with?(": ")
+              logger.debug("SSE keepalive received: #{line}")
+            end
+          end
+        end
+      else
+        logger.error("Failed to connect to SSE: #{response.code} #{response.message}")
+      end
+    end
+  end
+rescue Interrupt
+  logger.info("SSE connection interrupted by user")
+rescue => e
+  logger.error("SSE connection error: #{e.message}")
+end
+
+# Main client flow
+def main
+  logger = Logger.new($stdout)
+  logger.formatter = proc do |severity, datetime, _progname, msg|
+    "[CLIENT] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n"
+  end
+
+  puts "=== MCP SSE Test Client ==="
+  puts ""
+
+  # Step 1: Initialize session
+  logger.info("Initializing session...")
+
+  init_response = make_request(
+    nil,
+    "initialize",
+    {
+      protocolVersion: PROTOCOL_VERSION,
+      capabilities: {},
+      clientInfo: {
+        name: "sse-test-client",
+        version: "1.0",
+      },
+    },
+    "init-1",
+  )
+
+  if init_response[:error]
+    logger.error("Failed to initialize: #{init_response[:error]}")
+    exit(1)
+  end
+
+  session_id = init_response[:headers]["mcp-session-id"]&.first
+
+  if session_id.nil?
+    logger.error("No session ID received")
+    exit(1)
+  end
+
+  logger.info("Session initialized: #{session_id}")
+  logger.info("Server info: #{init_response[:body]["result"]["serverInfo"]}")
+
+  # Step 2: Start SSE connection in a separate thread
+  sse_thread = Thread.new { connect_sse(session_id, logger) }
+
+  # Give SSE time to connect
+  sleep(1)
+
+  # Step 3: Interactive menu
+  loop do
+    puts "\n=== Available Actions ==="
+    puts "1. Send custom notification"
+    puts "2. Test echo"
+    puts "3. List tools"
+    puts "0. Exit"
+    puts ""
+    print("Choose an action: ")
+
+    choice = gets.chomp
+
+    case choice
+    when "1"
+      print("Enter notification message: ")
+      message = gets.chomp
+      print("Enter delay in seconds (0 for immediate): ")
+      delay = gets.chomp.to_f
+
+      response = make_request(
+        session_id,
+        "tools/call",
+        {
+          name: "notification_tool",
+          arguments: {
+            message: message,
+            delay: delay,
+          },
+        },
+      )
+
+      if response[:body]["result"]
+        logger.info("Notification tool response: #{response[:body]["result"]["content"]}")
+      else
+        logger.error("Error: #{response[:body]["error"]}")
+      end
+
+    when "2"
+      print("Enter message to echo: ")
+      message = gets.chomp
+      make_request(session_id, "tools/call", { name: "echo", arguments: { message: message } })
+
+    when "3"
+      make_request(session_id, "tools/list")
+
+    when "0"
+      logger.info("Exiting...")
+      break
+
+    else
+      puts "Invalid choice"
+    end
+  end
+
+  # Clean up
+  sse_thread.kill if sse_thread.alive?
+
+  # Close session
+  logger.info("Closing session...")
+  make_request(session_id, "close")
+  logger.info("Session closed")
+rescue Interrupt
+  logger.info("Client interrupted by user")
+rescue => e
+  logger.error("Client error: #{e.message}")
+  logger.error(e.backtrace.join("\n"))
+end
+
+# Run the client
+if __FILE__ == $PROGRAM_NAME
+  main
+end