Fix replay 2D black canvas and journey UX clarity

Stored analysis overlays now use the decoded frame; latch resets and draw failures surface. Verified with bare-video, replay-wiring, visual_policy, and analysis-progress tests.

apps/studio/config/locales/zh_CN.json

@@ -218,6 +218,8 @@
     "replay_empty": "尚未打开录制\n点击下方「打开录制…」",
     "arrow_empty": "尚未采集图像\n请选择视频或摄像机后点击「运行」",
     "arrow_empty_tip": "运行或预览后在此显示形变箭头图",
+    "arrow_render_failed": "本帧无法绘制形变箭头\n请换一种视图，或重新加载视频",
+    "arrow_capture_unavailable": "当前无法取得采集图像用于叠加\n原始相机画面仍可在同一选择器中查看",
     "depth_unavailable": "本帧没有深度数据\n（不是深度为零，也未回退显示普通形变图）",
     "depth_scale": "深度色标 {low} – {high}",
     "depth_empty": "本帧深度全为 0（{pixels} px 中 0 个非零）：色标最低颜色是真实的零响应，不是缺数据",
@@ -448,6 +450,11 @@
     "phase_running": "采集中",
     "phase_error": "出错",
     "rail_video_name": "视频文件： {name}",
+    "rail_result_profile": "结果配置： {type}",
+    "rail_result_reused": "已复用缓存结果",
+    "rail_result_complete": "分析完成",
+    "rail_result_running": "正在分析…",
+    "rail_result_ready": "结果可用",
     "data_valid": "数据有效",
     "data_invalid": "无效样本 {count}",
     "calibrated": "已标定",
@@ -546,6 +553,10 @@
   },
   "analysis": {
     "title": "正在分析录像",
+    "title_reused": "正在使用已缓存的分析结果",
+    "title_complete": "分析完成",
+    "title_cancelled": "分析已取消",
+    "title_failed": "分析失败",
     "frames": "{written} / {expected} 帧",
     "segment": "分段 {index} / {count}",
     "elapsed": "已用 {seconds:.1f} s",