Read the analysis cache before refusing a pass, and own the cache root

Opening a recording while the session that recorded it was still live never reached
``stored_result()``, so the panel reported no result over a recording whose result was on
disk. The guard now follows the cache read, results move to the app's derived-data root
(swept at startup, the old in-recording root ignored), and the panel states which of the
four no-result states it is in, with the pass's own reason.
Verified: apps/studio 462/0/18, shared 431/0/1, autocal 358, ui_check 628/0, both gates
clean, real-GL snapshots per state.

apps/studio/config/locales/en_US.json

@@ -223,7 +223,10 @@
     "mesh3d_reset_tip": "Reset view: back to the framing the scene itself uses",
     "analysis_pipeline": "Analysis result (one finished pass)",
     "analysis_pipeline_tip": "This frame's arrows come from a stored analysis result rather than a chain running now; changing the threshold only changes which stored samples count as active.",
-    "analysis_empty": "the analysis result holds no frame here"
+    "analysis_empty": "the analysis result holds no frame here",
+    "replay_analysis_running": "this recording is being analysed: there are no arrows or depth to draw until it finishes. Progress and Cancel are on the analysis panel.",
+    "replay_analysis_failed": "there is no analysis result to draw: {reason}. Only the raw camera image can be shown here; once that is dealt with, Recompute from the video runs the pass again by hand.",
+    "replay_analysis_unavailable": "this is not a recording that can be analysed (its folder has no session.json, or no raw_*.mp4 segment): no pass can run, so this panel shows the raw camera image only. For forces and deformation from this video use View > Recompute forces from the video."
   },
   "chart": {
     "fn": "FN",
@@ -292,7 +295,8 @@
     "analysis_cancelled": "the analysis was cancelled: no complete result was written, so no playback is served",
     "analysis_no_source": "this recording has no video segment to analyse",
     "analysis_busy": "an analysis is already running: wait for it, or cancel it",
-    "analysis_grid_mismatch": "the current display settings moved the sample grid ({keys}); the stored candidate locations cannot serve it, so the replay keeps drawing the result's own grid"
+    "analysis_grid_mismatch": "the current display settings moved the sample grid ({keys}); the stored candidate locations cannot serve it, so the replay keeps drawing the result's own grid",
+    "analysis_no_chain": "this recording does not say which sensor and configuration produced it ({error}), so no result can be read and no pass can be run"
   },
   "record": {
     "label": "Record",

apps/studio/config/locales/zh_CN.json

@@ -223,7 +223,10 @@
     "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"
+    "analysis_empty": "分析结果里没有这一帧",
+    "replay_analysis_running": "正在分析这个录像：跑完之前这里没有箭头/深度可画，进度与取消在分析面板上。",
+    "replay_analysis_failed": "没有可画的分析结果：{reason}。这里只能显示原始相机图像；处理完之后可以点「由视频重算」再跑一遍。",
+    "replay_analysis_unavailable": "这不是一条可分析的录像（同目录没有 session.json，或没有 raw_*.mp4 分段）：没有能跑的分析，本面板只能显示原始相机图像。要从这段视频得到力值/形变，请用 视图 ▸ 从视频重算力值。"
   },
   "chart": {
     "fn": "FN",
@@ -292,7 +295,8 @@
     "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"
+    "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",
+    "analysis_no_chain": "这条录像没有说明用哪套传感器与配置录下来（{error}），所以既读不出结果也重算不了"
   },
   "record": {
     "label": "记录",