接入 Studio 多点标定的会话置零与状态记录

支持显式无载荷置零、处理线程内切换模型及完整标定包快照。shared、界面检查与兼容测试通过；Studio 全量仍有一项回放停止时序测试失败。

apps/studio/config/locales/en_US.json

@@ -1,4 +1,18 @@
 {
+  "multical": {
+    "video_zero": "I confirm 30 frames from the reference frame are unloaded",
+    "video_zero_tip": "For models requiring a session zero. Measure it from this interval; tracker reference alone does not imply zero load.",
+    "zero": "Unloaded zero",
+    "zero_confirm": "Remove all load and keep the sensor unloaded for the next 30 processed frames. For video, pause at a known unloaded interval first. Measure a new session zero now?",
+    "zero_pending": "Measuring unloaded zero from 30 frames. Keep all load removed.",
+    "ok": "Ready",
+    "zero_unavailable": "Unloaded zero required",
+    "no_contact": "No contact",
+    "outside_coverage": "Outside calibration coverage",
+    "coordinate_unmapped": "Contact position unavailable",
+    "out_of_range": "Outside calibrated force range",
+    "invalid_input": "Invalid measurement"
+  },
   "app": {
     "title": "Orisys Studio",
     "about_title": "About",