feat: 出图报错捕获真因 + 翻成前端友好提示(故事板)

老板/研发要求:有报错时把真因抓出来,做成前端友好提示。

- 捕获真实错误体(openai_compatible._raise_with_body):取代 raise_for_status()。
  yunqi 的真因(moderation_blocked / safety_violations=[sexual])只在 body 里,
  原来只剩状态行「400 Bad Request for url」→ 真因长期不可见。现在完整抓出。
- friendly_generation_error():把原始报错翻成中文友好提示(内容审核/超时/限流/
  凭证/参考图被拒…),前端直接展示;原始报错留 task.error_message 供研发排查。
- 故事板失败:友好提示存 shot.error_message;并撤回「重试 400」——审核拦截重试
  也是白拦,改成快速失败+提示,引导用户改措辞(如避免「胸罩/内衣/抚摸/贴身」)。
- 前端:失败帧缩略图加红色「⚠失败」角标(hover 看原因),主视图显示完整友好提示;
  不再灰着没反应。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/frontend/src/routes/pipeline.tsx

@@ -3150,6 +3150,12 @@ export function PipelinePage(props: {
                           <div className={`placeholder${url ? " has-mock-media" : ""}`} style={url ? mediaStyle(url) : undefined}>
                             <span className="ph-frame">场 {idx + 1}</span>
                             {shotBusy(shot) && <span className="sb-gen-veil" aria-hidden="true"><span className="spinner" /></span>}
+                            {/* 失败帧:角标红字「失败」,hover 看友好提示;不再灰着没反应(点该场到右侧看完整原因+重跑) */}
+                            {!shotBusy(shot) && shot.status === "failed" && (
+                              <span title={shot.error_message || "生成失败,点开本场查看原因并重跑"} style={{ position: "absolute", left: 6, top: 6, display: "inline-flex", alignItems: "center", gap: 3, padding: "2px 6px", borderRadius: 6, background: "var(--err, #d33)", color: "#fff", fontSize: 11, fontWeight: 600, zIndex: 2 }}>
+                                <svg width="11" height="11" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.2" strokeLinecap="round" strokeLinejoin="round"><path d="M12 9v4M12 17h.01" /><path d="M10.3 3.86 1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z" /></svg>失败
+                              </span>
+                            )}
                             {aid && <span className="sb-frame-rv" data-stop onClick={(e) => e.stopPropagation()}><ReviewBadge compact status={(reviews[aid] || shot.review_status || "") as ReviewStatus} error={shot.review_error} onSubmit={() => void submitAssetReview(aid)} busy={reviewBusyId === aid} /></span>}
                           </div>
                           <div className="nm">场 {idx + 1}</div>
@@ -3195,6 +3201,13 @@ export function PipelinePage(props: {
                               : <span className="pill neutral"><span className="dot"></span>待生成</span>)
                         : <span className="pill neutral"><span className="dot"></span>未生成</span>}
                     </div>
+                    {/* 失败原因·友好提示(后端已把 yunqi 真因翻成中文,如内容审核拦截 → 提示改措辞) */}
+                    {sbActiveShot?.status === "failed" && !activeBusy && sbActiveShot.error_message && (
+                      <div style={{ display: "flex", gap: 6, alignItems: "flex-start", color: "var(--err, #d33)", fontSize: "12.5px", lineHeight: 1.55, margin: "2px 0 10px", padding: "8px 10px", background: "rgba(211,51,51,.07)", borderRadius: 8 }}>
+                        <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" style={{ flexShrink: 0, marginTop: 1 }}><path d="M12 9v4M12 17h.01" /><path d="M10.3 3.86 1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z" /></svg>
+                        <span>{sbActiveShot.error_message}</span>
+                      </div>
+                    )}
                     <div className="muted-2" style={{ fontSize: "12px", lineHeight: 1.55, marginBottom: "10px" }}>每个场一张分镜图 · 可单独「重跑本场」只重出这一张,每场各自留历史版本,互不影响。</div>
                     <div className="muted mono" style={{ fontSize: "12px", fontWeight: 500, marginBottom: "6px", letterSpacing: ".04em" }}>// 整张风格提示词(重跑时生效,可编辑)</div>
                     <PromptBox