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/app/mcp-http-router.php

@@ -22,7 +22,8 @@ if ($token === null) {
 $handler = new McpHttpHandler(
     new McpDispatcher(
         RedmineClient::fromCredentials($env['redmine_url'], $env['redmine_api_key']),
-        new McpDebugLogger($env['mcp_debug_log'])
+        new McpDebugLogger($env['mcp_debug_log']),
+        $env['mcp_text_sanitization']
     ),
     $token,
     getenv('MCP_HTTP_PATH') ?: '/mcp'