Trail modes + the tip grows glued to the icon

«Показывать путь робота» is a three-way choice now: never / while
cleaning (the default — the line hides the moment the run ends) /
always (the only mode that also shows the faded previous run).
trail_mode rides next to the legacy bool, which still maps in.

The last segment no longer pops in when the next telemetry point
arrives: a rAF sampler drags a tip line's endpoint to the puck's
animated centre every frame, so the path visually pours out strictly
from under the icon. The sampler runs only while pucks exist and stops
itself.

src/i18n/en.json

@@ -361,7 +361,7 @@
   "vac.status_none": "The integration reports no coordinates — the robot will only be shown at its base",
   "vac.autocal": "Set up automatically",
   "vac.live": "Live position on the plan",
-  "vac.trail": "Show the cleaning trail",
+  "vac.trail": "Show the robot's path",
   "vac.cal_maps": "Calibrated maps: {maps}",
   "vac.autocal_no_rooms": "The integration reports no room list — use point calibration",
   "vac.autocal_no_match": "Room names did not match (need ≥3 in common) — use point calibration",
@@ -373,5 +373,8 @@
   "vac.fit": "Fit manually",
   "vac.fit_hint": "Drag the robot map into place, stretch by the corners",
   "vac.fit_rotate": "Rotate 90°",
-  "vac.fit_mirror": "Mirror"
+  "vac.fit_mirror": "Mirror",
+  "vac.trail_never": "Never",
+  "vac.trail_cleaning": "While cleaning",
+  "vac.trail_always": "Always"
 }

src/i18n/ru.json

@@ -361,7 +361,7 @@
   "vac.status_none": "Интеграция не отдаёт координаты — робот будет показан только на базе",
   "vac.autocal": "Настроить автоматически",
   "vac.live": "Живая позиция на плане",
-  "vac.trail": "Показывать след уборки",
+  "vac.trail": "Показывать путь робота",
   "vac.cal_maps": "Откалиброваны карты: {maps}",
   "vac.autocal_no_rooms": "Интеграция не отдаёт список комнат — используйте калибровку по точкам",
   "vac.autocal_no_match": "Не совпали имена комнат (нужно ≥3 общих) — используйте калибровку по точкам",
@@ -373,5 +373,8 @@
   "vac.fit": "Подогнать вручную",
   "vac.fit_hint": "Перетащите карту робота на место, растяните за уголки",
   "vac.fit_rotate": "Повернуть 90°",
-  "vac.fit_mirror": "Отразить"
+  "vac.fit_mirror": "Отразить",
+  "vac.trail_never": "Не показывать никогда",
+  "vac.trail_cleaning": "Во время уборки",
+  "vac.trail_always": "Показывать всегда"
 }