fix(spark_pet): egg auto-hatch, repeated spawning, taming, despawn, and nest selection

- Remove auto-advance timers from egg cold (180s) and warming (120s) stages
  so eggs only progress via player interaction (bonemeal → blaze powder)
- Remove fire/lava damage sensors from cold and warming stages to prevent
  fire-tick re-triggering advance_to_hatching on every tick (caused dragon spam)
- Shorten egg hatching despawn timer from 60-90s to 3s so egg disappears
  promptly after dragon spawns
- Fix taming: change tame_items "fish" → "cod" (pre-1.13 ID was broken;
  only salmon worked before)
- Change egg colour recipes from egg+nest_item to egg+dye (simpler UX):
  white_dye=white, brown_dye=brown, lime_dye=green, red_dye=red,
  cyan_dye=teal, black_dye=black
- Increase nest block selection_box height from 5px to 14px to match
  visible basket geometry so right-click entity_placer works on nest blocks

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

addon/spark_pet_BP/entities/spark_dragon.json

@@ -730,7 +730,7 @@
       "minecraft:jump.static": {},
       "minecraft:tameable": {
         "probability": 0.33,
-        "tame_items": ["fish", "salmon"],
+        "tame_items": ["cod", "salmon"],
         "tame_event": {
           "event": "silverlabs:on_tamed",
           "target": "self"