feat v1.36.2: per-source glow radius

- marker.glow_radius_cm overrides the global default per device (field
  in the marker dialog, HA units, placeholder = global default); pools
  and door sectors use the per-source radius
- backend schema; smoke_glow extended (11 checks); docs same-commit

src/i18n/en.json

@@ -291,5 +291,7 @@
   "marker.controls_label": "Controls light sources",
   "marker.controls_hint": "With tap action “Toggle”, a click flips all bound lights at once (any on → all off). The icon mirrors their state.",
   "marker.controls_filter": "Search lights and switches…",
-  "info.controls": "Controls"
+  "info.controls": "Controls",
+  "marker.glow_radius_label": "Glow radius (light-sources fill)",
+  "marker.glow_radius_hint": "empty = default from general settings"
 }