fix: polish vacuum map routes

Treat explicit empty route lists as authoritative, preserve them through single-space export, group deleted-space routes, and render vacuums from the immutable vacuum-only snapshot subset.

Issue: #443
User-Visible: yes

docs/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Removing a robot vacuum's last map route now keeps the route list explicitly
+  empty instead of reviving legacy calibration; routes to deleted spaces are
+  grouped clearly in the editor, and the live layer avoids rescanning every
+  non-vacuum device ([#443](https://github.com/Matysh/houseplan-card/issues/443)).
 - A robot vacuum's second and later maps can now be added: the editor asks for
   the target floor before saving the route, and a Home Assistant rejection no
   longer leaves a phantom local route

docs/CHANGELOG.ru.md

@@ -8,6 +8,11 @@
 
 ## Не выпущено
 
+- После удаления последнего маршрута карты робота список теперь остаётся явно
+  пустым и не возвращает старую калибровку; маршруты в удалённые пространства
+  собраны в понятную группу, а живой слой больше не перебирает повторно все
+  устройства, не являющиеся роботами
+  ([#443](https://github.com/Matysh/houseplan-card/issues/443)).
 - Вторую и последующие карты робота теперь можно добавить: сначала
   редактор просит выбрать этаж и только потом сохраняет маршрут,
   а отказ Home Assistant не оставляет ложную локальную запись

docs/CONFIG-COMPATIBILITY.md

@@ -84,10 +84,12 @@ validated boolean.
 and the pair `(source, map_id)` unique inside the marker. It requires no model
 or store version bump: absence reads as the historical behaviour.
 
-Reading is lossless in both directions. Without `map_routes` every valid
-`calibration[map_id]` is an effective route into the dock's space, so nothing
-is migrated on load and an ordinary save of other marker fields leaves the
-vacuum block untouched. The first explicit routing edit converts the whole
+Reading is lossless in both directions. When `map_routes` is absent or `null`,
+every valid `calibration[map_id]` is an effective route into the dock's space,
+so nothing is migrated on load and an ordinary save of other marker fields
+leaves the vacuum block untouched. Any array is explicit authority: an empty
+`map_routes: []` means that no route is configured and suppresses every
+retained legacy matrix. The first explicit routing edit converts the whole
 legacy dictionary at once and needs an exact source to do it; partial
 conversion is refused, and `calibration` is removed only after the config write
 succeeds.
@@ -97,7 +99,9 @@ never blocks an unrelated save, while an edited one must be valid or the write
 is refused atomically with `invalid_vacuum_map_route`. A full export/import
 round-trips routes verbatim. A single-space export drops routes that point at
 other spaces and counts them in `dropped_marker_links`, because their target
-would not exist in the imported document.
+would not exist in the imported document. If that removes the last explicit
+route, the export keeps `map_routes: []` rather than writing `null`, so a later
+import cannot make legacy calibration authoritative again.
 
 Downgrade: an older frontend ignores `map_routes` and falls back to the legacy
 `calibration` dictionary, which the conversion removed — such a plan shows the

docs/USER-GUIDE.ru.md

@@ -1507,6 +1507,9 @@ Map Extractor, dreame-vacuum (Tasshack) и Valetudo-подобные камер
 текущая карта. Пока карта не сопоставлена, не откалибрована или неотличима
 от другой, робот не рисуется нигде — у дока появляется предупреждение
 с причиной.
+Маршруты, которые ссылаются на уже удалённое пространство, собраны в конце
+списка в отдельной группе «Пространство удалено». Их можно сопоставить другому
+пространству или удалить; House Plan не переносит такие маршруты автоматически.
 Если максимальное расхождение больше 40 см, настройки не меняются до выбора
 «Применить». Можно вместо этого открыть ручную подгонку или отменить операцию.
 

docs/VACUUM.md

@@ -191,13 +191,16 @@ marker.vacuum = {
 }
 ```
 
-All fields are optional and old plans remain readable. Without `map_routes`
-every valid `calibration[map_id]` is read as an effective route into the dock's
-space, so a plan made before #162 renders byte for byte as before. The first
-explicit routing edit converts the whole dictionary at once — all matrices or
-none — and needs an exact source to do it; `calibration` is dropped only after
-the config write succeeds. Where both exist, `map_routes` is the only
-authority and the legacy dictionary takes no part in rendering.
+All fields are optional and old plans remain readable. When `map_routes` is
+absent or `null`, every valid `calibration[map_id]` is read as an effective
+route into the dock's space, so a plan made before #162 renders byte for byte
+as before. Any array is explicit authority: `map_routes: []` means that no map
+is assigned and must not revive a retained legacy matrix. The first explicit
+routing edit converts the whole dictionary at once — all matrices or none —
+and needs an exact source to do it; `calibration` is dropped only after the
+config write succeeds. Where both exist, `map_routes` is the only authority
+and the legacy dictionary takes no part in rendering. A single-space export
+also preserves an explicit empty array when all foreign routes are filtered.
 
 A stored run carries the route that wrote it:
 `{ route_id, source, map_id, started, ended, points }`. A run recorded before