合并最新 staging 到侧栏重画这支

校正提速已经在测试线上。更新日志、缺陷记录和任务索引两边都留下。这单自己的修复还没开始。

Co-Authored-By: Grok (agent loop)

frontend/src/lib/rectification-agentic/v9/engine-client.ts

@@ -330,17 +330,27 @@ async function readEngineJsonTimed(
     const elapsedMs = Date.now() - started;
     const data = await response.json().catch(() => null);
     if (!response.ok) {
-      const kind: EngineCallFailureKind = response.status === 429 ? "busy" : "http_error";
+      const errorText = data && typeof data === "object"
+        ? String((data as Record<string, unknown>).error ?? (data as Record<string, unknown>).message ?? "")
+        : "";
+      const errorCode = data && typeof data === "object"
+        ? String((data as Record<string, unknown>).error_code ?? "")
+        : "";
+      const tooManyCandidates = response.status === 400
+        && (errorCode === "too_many_candidates" || errorText.includes("too_many_candidates"));
+      const kind: EngineCallFailureKind = response.status === 429
+        ? "busy"
+        : tooManyCandidates
+          ? "bad_payload"
+          : "http_error";
       logEngineCallFailure({
         path,
         kind,
         elapsedMs,
         httpStatus: response.status,
       });
-      const message = data && typeof data === "object"
-        ? String((data as Record<string, unknown>).error ?? (data as Record<string, unknown>).message ?? `Jyotish API ${response.status}`)
-        : `Jyotish API ${response.status}`;
-      throw new RectificationEngineError(persistenceCodeForKind(kind), message, {
+      const message = errorText || `Jyotish API ${response.status}`;
+      throw new RectificationEngineError(tooManyCandidates ? "too_many_candidates" : persistenceCodeForKind(kind), message, {
         kind,
         httpStatus: response.status,
         retryAfterSeconds: retryAfterFromHeaders(response.headers) ?? undefined,