fix(addons): bring silverlabs packs into schema compliance

- recipes: add unlock { context: always_unlocked } to all spark_pet and lobby_transfer recipes (1.20+ requirement) — fixes mc-lobby crash loop
- spark_dragon entity_sensor: wrap in subsensors[] and convert sensor_range → range [a,b] per 1.21 schema
- anthrax_cat interact: wrap event/filters in on_interact to match Bedrock 1.21 interact schema
- block format_version: bump mailbox and smart_crafting_table to 1.21.60
- item icons: replace { texture: X } with shorthand string form
- heyhe_egg description: replace bare category with menu_category block

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

addon/spark_pet_BP/entities/spark_dragon.json

@@ -190,15 +190,14 @@
           "reselect_targets": true
         },
         "minecraft:entity_sensor": {
-          "sensor_range": 500,
-          "relative_range": false,
-          "minimum_count": 1,
-          "event_filters": {
-            "test": "is_family",
-            "subject": "other",
-            "value": "whistle_signal"
-          },
-          "event": "silverlabs:whistle_called"
+          "subsensors": [
+            {
+              "range": [500, 500],
+              "minimum_count": 1,
+              "event": "silverlabs:whistle_called",
+              "event_filters": { "test": "is_family", "subject": "other", "value": "whistle_signal" }
+            }
+          ]
         },
         "minecraft:behavior.melee_attack": {
           "priority": 2,