feat(anthrax-cat): add Maneki-neko lucky cat decoration addon, remove easter egg

- New silverlabs:anthrax_cat entity: sitting cat with waving paw animation,
  idle body bob, look-at-player, fortune message + bell sound on interact
- Custom 64x64 texture (cream/white, red bib, gold coin, orange tabby patches)
- Custom geometry: body, head, ears, raised left arm, tail, bib, coin bones
- Removed easter egg addon mounts from all 4 servers (lobby + 3 child worlds)
- Anthrax Cat mounted on all 4 servers

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

addon/anthrax_cat_BP/entities/anthrax_cat.json

@@ -0,0 +1,79 @@
+{
+  "format_version": "1.21.0",
+  "minecraft:entity": {
+    "description": {
+      "identifier": "silverlabs:anthrax_cat",
+      "is_spawnable": true,
+      "is_summonable": true,
+      "is_experimental": false
+    },
+    "component_groups": {
+      "silverlabs:active": {
+        "minecraft:interact": {
+          "interactions": [
+            {
+              "interact_text": "action.interact.fortune",
+              "play_sounds": "note.bell",
+              "event": "silverlabs:interacted"
+            }
+          ]
+        }
+      }
+    },
+    "components": {
+      "minecraft:type_family": {
+        "family": ["anthrax_cat", "decoration"]
+      },
+      "minecraft:physics": {
+        "has_gravity": true,
+        "has_collision": true
+      },
+      "minecraft:pushable": {
+        "is_pushable": false,
+        "is_pushable_by_piston": false
+      },
+      "minecraft:collision_box": {
+        "width": 0.7,
+        "height": 0.95
+      },
+      "minecraft:knockback_resistance": {
+        "value": 1.0
+      },
+      "minecraft:damage_sensor": {
+        "triggers": [
+          {
+            "cause": "all",
+            "deals_damage": false
+          },
+          {
+            "cause": "override",
+            "deals_damage": true
+          }
+        ]
+      },
+      "minecraft:health": {
+        "value": 20,
+        "max": 20
+      },
+      "minecraft:persistent": {},
+      "minecraft:nameable": {},
+      "minecraft:behavior.look_at_player": {
+        "priority": 1,
+        "target_distance": 8.0,
+        "look_time": [2, 6],
+        "probability_per_distance": 0.02
+      },
+      "minecraft:behavior.random_look_around": {
+        "priority": 2
+      }
+    },
+    "events": {
+      "minecraft:entity_spawned": {
+        "add": {
+          "component_groups": ["silverlabs:active"]
+        }
+      },
+      "silverlabs:interacted": {}
+    }
+  }
+}