Sanitize noisy MCP text fields by default

Clean control and invisible junk from tool result text fields to reduce token waste while preserving readable Unicode. Add an MCP_TEXT_SANITIZATION toggle and regression tests for enabled and disabled behavior.

redMCP/bin/redmcp-server.php

@@ -15,7 +15,8 @@ $env = McpEnvironment::load(__DIR__ . '/../.env');
 $server = new McpStdioServer(
     new McpDispatcher(
         RedmineClient::fromCredentials($env['redmine_url'], $env['redmine_api_key']),
-        new McpDebugLogger($env['mcp_debug_log'])
+        new McpDebugLogger($env['mcp_debug_log']),
+        $env['mcp_text_sanitization']
     )
 );
 $server->run();