fix(claude): normalize adaptive auto effort (#3792)

Claude adaptive requests without an explicit effort are normalized to
output_config.effort: "high" instead of forwarding the unsupported
literal value "auto" which Anthropic rejects with HTTP 400.

open-sse/translator/concerns/thinkingUnified.js

@@ -246,7 +246,7 @@ function applyFormat(fmt, body, cfg, caps, supportedLevels) {
       if (canDisable) body.thinking = { type: "adaptive" };
       else delete body.thinking;
       const level = toLevel(eff);
-      body.output_config = { effort: level === "xhigh" ? "high" : level };
+      body.output_config = { effort: level === "xhigh" || level === "auto" ? "high" : level };
       break;
     }
     case "claude-budget": {