裸视频可分析：生成工作区、设置提示、逐帧力与按来源选画笔

pass 只认 frames.csv 与 session.json，裸视频此前因此只能播放；现在为它在应用自己的目录里生成
这两份文件并复用既有链路，链路重算的力按帧存入结果并标注为「重算」，box 的空白箭头画布改按帧
来源走共享画笔。
apps/studio/tests 497 项、shared/tests 471 项（2 个已知墙钟失败）、autocal 358 项、ui_check 634 项
均 0 失败，lint_gate 与 doc_lint 无发现；真实 GL 快照见 .scratch/bare-video/snapshots。

apps/studio/docs/replay-analysis.md

@@ -9,7 +9,8 @@
 一次约 4.8 分钟。Part A 把这一遍跑一次，只存回放真正要画的东西。
 
 格式版本从 1 升到 2：帧记录里多了深度通道。旧结果不会被误读 —— 版本不符直接
-`AnalysisFormatError`，重跑一遍即可（结果本来就是可重算的）。
+`AnalysisFormatError`，重跑一遍即可。力的通道**没有**再升版本：它追加在记录最后，老读端按原偏移
+仍能读出同一帧，只是没有力（第 1 节末）。
 
 ## 1. 结果模型
 
@@ -43,9 +44,27 @@ zlib level 6。
 而且一旦有深度值落在岛外就会**静默丢掉一个测量**。
 
 `provenance` 随结果存：算法版本、传感器配置及其内容哈希、标定 id、单位、参考帧 id、首个输出
-帧 id、解码偏移、逐通道的"重算/记录"标记（`flow`、`depth` 重算，`forces` 记录）、`complete`
-标志与计数。`counts` 另记 `depth_frames` / `depth_nonzero_frames` / `depth_nonzero_max` /
-`depth_pixels` 与实测的 `frame_record_bytes`，进度面板和"这一帧为什么是空的"都读它。
+帧 id、解码偏移、逐通道的"重算/记录"标记（`flow`、`depth` 重算；`forces` 见第 1.1 节）、
+`synthetic` 与 `synthetic_source`、`complete` 标志与计数。`counts` 另记深度与力通道的计数与实测
+的 `frame_record_bytes`，进度面板和"这一帧为什么是空的"都读它。
+
+**帧记录可以再带一份力，追加在最后。** 裸视频没有 `forces.csv`，pass 就把链路算出的力按帧存下：
+`FRAME_FLAG_FORCE` 后接六个 float32 与两个标志位，28 B/帧。版本不变的理由见开头；读数取不到时存
+`NaN`。
+
+### 1.1 裸视频的输入：生成的工作区
+
+pass 只认一种输入形状（一个目录里的 `frames.csv`、`session.json` 与 `raw_*.mp4`），而形状本身是
+好的：帧身份、时间与链路都来自录制自己的元数据。裸视频因此**不新增第二条代码路径**，而是把这两个
+文件为它*生成*出来（`analysis/bare_video.py`）：`frames.csv` 给容器每一帧一行
+（`t_rel_s = index / fps`），`session.json` 给出 `device`/`stats`/`files` 与一个 `synthetic` 块；
+裸视频只有容器时间，所以容器的钟**就是**信号时间（第 5 节）。
+
+凡是 `recording_identity` 会哈希的字段都只由**视频与所选配置**决定，不含任何时钟：重开同一条视频
+就是同一个 key；标定进 key 的是**文件内容**的摘要。视频以 `raw_0001.mp4` 放进工作区（能硬链接就
+链接）：一个文件就是一段，因此**多文件输入直接拒绝**并列出文件名。工作区写在应用自己的派生数据根
+（`paths.video_workspace_dir()`），**绝不写在操作员视频旁边**；`synthetic` 块被 pass 抄进
+`provenance.synthetic`/`synthetic_source`，重算出来的测量因此不可能被当成记录的测量读。
 
 ## 2. Keyframe：候选位置与有效掩码
 

apps/studio/src/orisys_studio/ui/force_plots.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import logging
 import time
 
 import numpy as np
@@ -30,6 +31,8 @@ from PySide6.QtWidgets import (
 from orisys_studio.ui import icons
 from orisys_studio.ui.icons import ICON_SIZE
 
+logger = logging.getLogger(__name__)
+
 try:
     import pyqtgraph as pg
 except ImportError as exc:  # pragma: no cover
@@ -190,6 +193,11 @@ class ForcePlotsPanel(QFrame):
         #: True once a source is attached (either kind). ``_store is None`` was
         #: the old proxy for this and could not express a disk source.
         self._source_ready = False
+        #: Non-empty when there is no trace to draw *and that is a fact about the input*:
+        #: a bare video whose pass has not run, or a profile whose chain produced no force
+        #: for it. The mode line states it rather than leaving an empty plot under wording
+        #: that implies data is on its way.
+        self._source_absent_reason = ""
         #: The live store to return to when a recording source is detached.
         self._live_store = None
         self._mode = "follow"
@@ -473,8 +481,10 @@ class ForcePlotsPanel(QFrame):
         for i, plot in enumerate(self.plots):
             try:
                 plot.getViewBox().setBackgroundColor(QColor(bg))
-            except Exception:
-                pass
+            except Exception:  # noqa: BLE001 - a view box that refuses a colour
+                # Reported rather than swallowed: a plot left on the previous theme's
+                # background is a visible defect, and only this line says why it happened.
+                logger.debug("could not set the chart background", exc_info=True)
             for axis_name in ("left", "bottom"):
                 axis = plot.getAxis(axis_name)
                 axis.setPen(axis_pen)
@@ -842,6 +852,7 @@ class ForcePlotsPanel(QFrame):
         self._live_store = store
         self._source = StoreCurveSource(store)
         self._source_ready = store is not None
+        self._source_absent_reason = ""
         self._on_source_changed()
 
     def set_recording_source(self, reader) -> None:
@@ -850,6 +861,29 @@ class ForcePlotsPanel(QFrame):
 
         self._source = RecordingCurveSource(reader)
         self._source_ready = True
+        self._source_absent_reason = ""
+        self._on_source_changed()
+
+    def set_curve_source(self, source, *, reason: str = "") -> None:
+        """Attach any curve source, or say why there is no trace to draw.
+
+        The charts used to have exactly two states: the live session store, and one
+        recording's ``forces.csv``. A bare video has neither — the force there is the
+        analysis pass's own recomputation, stored inside the result — and the panel has to
+        be able to read it *and* say which of the two it is reading, because a recomputed
+        trace and a recorded one are different claims about the same footage.
+
+        ``source is None`` with a ``reason`` is a state, not an empty chart: the mode line
+        states that reason instead of leaving "following live" over a flat plot.
+        """
+        if source is None:
+            self._source = StoreCurveSource(self._live_store)
+            self._source_ready = False
+            self._source_absent_reason = str(reason or "")
+        else:
+            self._source = source
+            self._source_ready = True
+            self._source_absent_reason = ""
         self._on_source_changed()
 
     def clear_recording_source(self) -> None:
@@ -857,8 +891,18 @@ class ForcePlotsPanel(QFrame):
         if self.is_recording_source():
             self.set_store(self._live_store)
 
+    def curve_kind(self) -> str:
+        """Which kind of source is attached: ``memory``, ``disk`` or ``analysis``."""
+        return str(getattr(self._source, "kind", ""))
+
     def is_recording_source(self) -> bool:
-        return str(getattr(self._source, "kind", "")) == "disk"
+        """True when the curves are read from a file rather than the live session.
+
+        Both a recording's own CSV and a result's recomputed trace count: neither is the
+        live store, and every caller that asks this question (the "back to latest" button,
+        the redraw paths) means "not the live data" rather than "specifically disk".
+        """
+        return self.curve_kind() in ("disk", "analysis")
 
     def _switch_unit(self, unit: str) -> None:
         """Move the live buffer to another display unit without misreading it.
@@ -1274,8 +1318,22 @@ class ForcePlotsPanel(QFrame):
         continue)") did not fit next to the header's icon buttons at 1280–1440 px
         in English and was simply cut mid-word, so the parenthetical lives in the
         tooltip and the label stays a name.
+
+        Three sources can be attached, and two of them are *files* — a recording's own
+        ``forces.csv`` and an analysis result's recomputed trace. They are different
+        claims about the same footage, so they get different names rather than one
+        "replay" that would hide which number came from where.
         """
-        if self.is_recording_source():
+        if self._source_absent_reason:
+            key = "chart.mode_no_trace"
+            self.mode_label.setText(t(key, reason=self._source_absent_reason))
+            self.mode_label.setToolTip(t("chart.mode_no_trace_tip"))
+            self.btn_latest.setEnabled(False)
+            self.btn_overview.setEnabled(False)
+            return
+        if self.curve_kind() == "analysis":
+            key = "chart.mode_recomputed"
+        elif self.is_recording_source():
             key = "chart.mode_replay"
         else:
             key = "chart.mode_browse" if self._mode == "browse" else "chart.mode_follow"
@@ -1397,6 +1455,7 @@ class ForcePlotsPanel(QFrame):
             try:
                 ymin, ymax = plot.getViewBox().viewRange()[1]
             except Exception:  # noqa: BLE001 - a view box mid-construction
+                logger.debug("could not read the chart's view range", exc_info=True)
                 continue
             zero_line.setVisible(bool(ymin <= 0.0 <= ymax))