fix: HA light target — brightness source, transition=0, dashboard type label

- Add brightness_value_source_id to HALightOutputTarget model, to_dict,
  from_dict, update_fields, register_with_manager, API response
- Wire value stream in HALightTargetProcessor: acquire/release on
  start/stop, multiply brightness in _update_lights loop
- Fix transition=0 not saving (parseFloat("0") || 0.5 was falsy)
- Fix dashboard showing "Key Colors" for HA targets — now "Home Assistant"
- Fix dashboard FPS showing 0/2 — HA targets show target/target
- Add CSS source subtitle to HA target dashboard cards

custom_components/wled_screen_controller/strings.json

@@ -54,13 +54,25 @@
           "unavailable": "Unavailable"
         }
       },
-      "rectangle_color": {
-        "name": "{rectangle_name} Color"
+      "mapped_lights": {
+        "name": "Mapped Lights"
       }
     },
     "number": {
       "brightness": {
         "name": "Brightness"
+      },
+      "ha_light_update_rate": {
+        "name": "Update Rate"
+      },
+      "ha_light_transition": {
+        "name": "Transition"
+      },
+      "ha_light_min_brightness": {
+        "name": "Min Brightness"
+      },
+      "ha_light_color_tolerance": {
+        "name": "Color Tolerance"
       }
     },
     "select": {