Make the rail reset zero the sensor in live and the display in replay

The replay view disabled a control whose display reset is exactly what an
operator wants there, and the bare "Reset" hid that the live one zeroes the
sensor tracker; the label, tooltip and status line now name the target, and
Ctrl+R follows the view. Verified with the studio suite, ui_check (628
checks) and real-GL rail snapshots of both views.

apps/studio/config/locales/en_US.json

@@ -45,7 +45,8 @@
     "run": "Run / Stop",
     "stop": "Cancel acquisition",
     "preview": "Preview / Stop preview",
-    "reset": "Reset tracker",
+    "reset": "Reset sensor tracker",
+    "reset_display": "Reset display",
     "reset_view": "Reset views",
     "reset_view_tip": "Put the chart window, cursor and 3D camera back to their defaults (F8). Touches neither the device nor the zero estimate.",
     "pause": "Pause / resume (F7)",
@@ -133,8 +134,11 @@
     "playback_disabled": "Open a recorded video first (“Choose a recorded video…” at the top left)",
     "playback_needs_recording": "This video has no recording beside it (no forces.csv): replay needs a recording; to just watch the video use View ▸ Recompute forces from the video",
     "playback_video_only": "Play this video (no recording beside it: the picture plays, the force charts are empty)",
-    "reset": "Reset",
-    "reset_tip": "Zero the device tracker. This affects the zero point only, never the view — to put the views back use View → Reset views.",
+    "reset_sensor": "Reset sensor",
+    "reset_sensor_tip": "Zero the sensor tracker (the device's own zero). Zeroing it also restarts the display baseline, so the curves and the value cards re-learn their zero from the next quiet samples; the curve history is kept — View ▸ Reset views (F8) clears the views.",
+    "reset_sensor_unavailable": "Zero the sensor tracker — available while a session is running (start a run first).",
+    "reset_display": "Reset display",
+    "reset_display_tip": "Clear the accumulated display: the curves, cursor and value cards go back to their defaults and the replay returns to the start of the recording. There is no device session in this view, so nothing of the device is touched; the 3D camera is View ▸ Reset views (F8).",
     "pause": "⏸  Pause",
     "pause_resume": "▶",
     "pause_tip": "Pause the computation and the display (F7): no flow, depth or contact is computed, the picture holds its last frame, and the device stays connected for an immediate resume. A recording that spans a pause has a gap.",
@@ -424,8 +428,9 @@
     "capture_slow": "The camera delivers less than the configured frame rate: {detail}. The recording keeps the real rate. This is a capture-side (camera/driver) matter that software cannot change: use a camera that really does deliver 30 fps — after checking that the cable or port is not slowing this one down — and measure again.",
     "video_ended": "Video ended",
     "camera_disconnected": "Camera disconnected",
-    "reset_ok": "Tracker reset",
-    "reset_pending": "Zeroing requested; waiting for the acquisition thread to confirm…",
+    "reset_ok": "Sensor tracker reset (the display baseline restarts)",
+    "reset_pending": "Sensor zero requested; the display baseline restarts once the acquisition thread confirms…",
+    "reset_display": "Display reset: curves back to their defaults, replay at the start",
     "view_reset": "Views reset",
     "paused": "Paused: nothing is computed, the device stays connected",
     "resumed": "Resumed",

apps/studio/config/locales/zh_CN.json

@@ -45,7 +45,8 @@
     "run": "运行 / 停止",
     "stop": "取消采集",
     "preview": "预览 / 停止预览",
-    "reset": "重置追踪器",
+    "reset": "重置传感器追踪器",
+    "reset_display": "复位显示",
     "reset_view": "复位视图",
     "reset_view_tip": "把曲线窗口、游标与三维视角恢复为默认（F8）。不改动设备，也不清除零点估计。",
     "pause": "暂停 / 继续（F7）",
@@ -133,8 +134,11 @@
     "playback_disabled": "先打开一段录制视频（左上「选择录制视频…」）",
     "playback_needs_recording": "这段视频旁边没有记录（缺 forces.csv）：回放需要一条记录；只想看视频请用 视图 ▸ 从视频重算力值",
     "playback_video_only": "播放这段视频（没有配套记录：可以看画面，力曲线为空）",
-    "reset": "重置",
-    "reset_tip": "把设备追踪器归零（清零）。只影响零点，不动界面；想恢复视图请用「视图 → 复位视图」。",
+    "reset_sensor": "重置传感器",
+    "reset_sensor_tip": "把传感器追踪器归零（清零），这是设备自己的零点。归零同时会重新估计显示基线：曲线与数字卡按之后的静默样本重新学习零点；曲线历史保留 —— 要清空视图请用「视图 → 复位视图」（F8）。",
+    "reset_sensor_unavailable": "把传感器追踪器归零 —— 仅在采集会话运行时可用（先点「运行」）。",
+    "reset_display": "复位显示",
+    "reset_display_tip": "清空累积的显示：曲线、游标与数字卡恢复默认，回放回到录像开头。本视图没有设备会话，不会改动设备；三维视角请用「视图 → 复位视图」（F8）。",
     "pause": "⏸  暂停",
     "pause_resume": "▶",
     "pause_tip": "暂停计算与显示（F7）：不再做光流/深度/接触计算，画面停在最后一帧，设备保持连接，随时可继续。跨过暂停的记录会有一段空档。",
@@ -424,8 +428,9 @@
     "capture_slow": "摄像头交付的帧率低于配置值：{detail}。记录会按实际帧率保存。这是采集端（摄像头/驱动）的问题，软件改不了：换一颗真能交付 30 fps 的摄像头，或先确认线材/端口没有把它降速，然后再测。",
     "video_ended": "视频已结束",
     "camera_disconnected": "摄像机已断开",
-    "reset_ok": "追踪器已重置",
-    "reset_pending": "已请求归零，等待采集线程确认…",
+    "reset_ok": "传感器追踪器已重置（显示基线重新估计）",
+    "reset_pending": "已请求传感器归零，采集线程确认后显示基线重新估计…",
+    "reset_display": "显示已复位：曲线恢复默认，回放回到开头",
     "view_reset": "视图已复位",
     "paused": "已暂停：不再计算，设备保持连接",
     "resumed": "已继续",