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/heyhe_pet_BP/items/heyhe_egg.json

@@ -3,13 +3,11 @@
   "minecraft:item": {
     "description": {
       "identifier": "silverlabs:heyhe_egg",
-      "category": "Nature"
+      "menu_category": { "category": "nature" }
     },
     "components": {
       "minecraft:max_stack_size": 16,
-      "minecraft:icon": {
-        "texture": "heyhe_egg"
-      },
+      "minecraft:icon": "heyhe_egg",
       "minecraft:entity_placer": {
         "entity": "silverlabs:heyhe_egg",
         "dispense_on": [