fix: preserve code agent sessions after turn failures

internal/cloud/code-agent-session-lifecycle.ts

@@ -18,7 +18,7 @@ export const CODE_AGENT_SESSION_STATUS_ALIASES = Object.freeze({
 });
 
 const ACTIVE_LIFECYCLE_STATUSES = new Set(["creating", "ready", "busy", "idle"]);
-const TERMINAL_LIFECYCLE_STATUSES = new Set(["interrupted", "expired", "failed"]);
+const TERMINAL_LIFECYCLE_STATUSES = new Set(["interrupted", "expired"]);
 
 export function normalizeCodeAgentSessionLifecycleStatus(value, { fallback = null } = {}) {
   const text = String(value ?? "").trim().toLowerCase();
@@ -75,7 +75,7 @@ export function codeAgentSessionLifecycleSummary(input = {}) {
     (gateBlocked && !concreteLifecycleBlock);
   if ((fallbackUsed || degraded) && !hasSession) status = "failed";
   const requiresNewSession = status ? TERMINAL_LIFECYCLE_STATUSES.has(status) : degraded || fallbackUsed;
-  const reusable = status ? ACTIVE_LIFECYCLE_STATUSES.has(status) && status !== "creating" && degraded !== true : false;
+  const reusable = status ? ((ACTIVE_LIFECYCLE_STATUSES.has(status) && status !== "creating") || status === "failed") && degraded !== true : false;
   const newSession = reused === false || (hasSession && !reused && !requiresNewSession);
   const reasonCode = firstText(
     input.degradationReasonCode,
@@ -171,8 +171,8 @@ function lifecyclePresentation({ status, rawStatus, reused, newSession, degraded
   if (status === "failed") {
     return {
       label: "会话失败",
-      action: "new_session",
-      userMessage: "当前 Code Agent session 已失败，需重新发送建立新会话。"
+      action: "continue",
+      userMessage: "当前 Code Agent turn 已失败；session/thread 已保留，可继续发送下一条消息。"
     };
   }
   if (status === "interrupted") {