Serve replay playback from a cached analysis result

Replay re-ran the SDK chain on every seek; Part A's pass stores the flow
samples once. Opening a recording now reuses a compatible result or runs the
pass behind a progress/cancel surface, and one cursor with two modes
(recorded CSV, analysed) feeds the charts, the 2D canvas and the 3D pane by
frame id. A threshold, colour or idle-dot change redraws from the stored
frames and writes nothing; a cancelled pass is reported and never played.

Verified: apps/studio/tests 440 items / 0 failed / 18 skipped (15 new, no
existing assertion changed); shared 417 / 0 / 1; autocal 358.

apps/studio/config/locales/zh_CN.json

@@ -155,7 +155,8 @@
     "units_newton": "牛顿",
     "units_raw": "原始",
     "settings": "设置",
-    "settings_tip": "展开或收起单位、记录模式与预览"
+    "settings_tip": "展开或收起单位、记录模式与预览",
+    "stopped_analysis": "分析"
   },
   "units": {
     "newton_short": "N",
@@ -218,7 +219,10 @@
     "mesh3d_rejected": "三维场景被拒绝：{message}\n只影响三维视图：采集、记录与力曲线照常工作。",
     "mesh3d_unavailable_gl_reason": "本机无法使用三维显示：{reason}\n采集、记录与力曲线照常工作。",
     "mesh3d_settings_tip": "三维显示设置（视角、外壳、色标、显示频率）",
-    "mesh3d_reset_tip": "复位视角：回到场景自带的取景"
+    "mesh3d_reset_tip": "复位视角：回到场景自带的取景",
+    "analysis_pipeline": "分析结果（已跑完的一遍）",
+    "analysis_pipeline_tip": "这一帧的箭头来自存下来的分析结果，不是此刻在跑的链路；换阈值只改变哪些样本算「有效」，不会重算。",
+    "analysis_empty": "分析结果里没有这一帧"
   },
   "chart": {
     "fn": "FN",
@@ -278,7 +282,16 @@
     "warn_config_missing": "找不到配置哈希，无法校验重算一致性",
     "warn_rows_skipped": "有无法解析的 CSV 行被跳过",
     "warn_frames_dropped": "有帧在队列溢出时丢失，仅保留索引记录（回放显示为“该帧未录制”）",
-    "warn_out_of_order": "该录制由旧版本写入，行序不是时间序；回放已按时间重排，区间边界可能与当时不同"
+    "warn_out_of_order": "该录制由旧版本写入，行序不是时间序；回放已按时间重排，区间边界可能与当时不同",
+    "analysis_empty": "这个分析结果里没有可显示的帧",
+    "analysis_unreadable": "这一帧读不出来（{error}）",
+    "analysis_complete": "已用分析结果回放：{frames} 帧，游标按信号时间（录制自己的 frames.csv）",
+    "analysis_reused": "找到了现成的分析结果，直接回放：{frames} 帧",
+    "analysis_failed": "分析未完成（{reason}）：不提供回放。可以重新分析，或关闭「从视频重算」看录制的 forces.csv",
+    "analysis_cancelled": "分析已取消：未写出完整结果，因此不提供回放",
+    "analysis_no_source": "这段录制没有可用于分析的视频分段",
+    "analysis_busy": "分析进行中：先等待或取消当前这一遍",
+    "analysis_grid_mismatch": "当前显示设置改了采样网格（{keys}），存下来的候选位置无法服务它：回放仍按结果自己的网格绘制"
   },
   "record": {
     "label": "记录",
@@ -497,6 +510,27 @@
     "severity_info": "提示",
     "severity_warning": "警告",
     "severity_error": "错误",
-    "stats": "已显示 {displayed} · 显示跳帧 {dropped} · 合成 {compose} ms · 绘制 {paint} ms"
+    "stats": "已显示 {displayed} · 显示跳帧 {dropped} · 合成 {compose} ms · 绘制 {paint} ms",
+    "source_analysis": "分析结果：已跑完的一遍，按帧读取",
+    "source_analysis_tip": "画面来自存下来的分析结果：算法链路已经跑完并写入缓存，拖动时间轴与播放都只是读文件。换阈值或配色不会重算。"
+  },
+  "analysis": {
+    "title": "正在分析录像",
+    "subtitle": "只跑一遍：之后拖动时间轴、播放与单步都只是读结果",
+    "stage_open": "打开链路",
+    "stage_frames": "逐帧分析",
+    "stage_write": "写入结果",
+    "frames": "{written} / {expected} 帧",
+    "segment": "分段 {index} / {count}",
+    "elapsed": "已用 {seconds:.1f} s",
+    "cancel": "取消",
+    "cancelling": "正在取消…",
+    "cancel_tip": "取消这一遍：已完成的帧会留下，但结果会被标记为未完成，永远不会被当作有效结果回放",
+    "reused": "已有结果，无需重算",
+    "complete": "分析完成：{frames} 帧，用时 {seconds:.1f} s",
+    "cancelled": "分析已取消（{frames} 帧已写完，结果标记为未完成）",
+    "failed": "分析失败：{reason}",
+    "incomplete": "结果未完成：{reason}",
+    "blocked": "正在采集：停止后再分析"
   }
 }