chore(pack): make config files opt-in and ship a PetProtect default

.packwizignore ignored config/ and defaultconfigs/ wholesale. They are now
ignored per-entry (config/*) with deliberately authored files re-included at
the bottom of the file, so one config can ship without any risk of pulling
every runtime-generated config into the index - which matters because this
repo doubles as a server directory.

Ships config/petprotect.json disabling BOTH pet damage and death protection.
PetProtect's isInvulnerableTo mixin gates on prevent_pet_damage alone, so
disabling prevent_pet_death by itself leaves pets invulnerable to nearly all
damage and Pet Cemetery's death -> collar -> respawn loop still never fires.
prevent_pet_attack remains true, so pets are not provoked into fights.

Without this file the two mods cancel each other: PetProtect's defaults keep
pets immortal, so Pet Cemetery is dead weight.

The config installs on clients as well as the server; that is harmless since
petprotect itself is side = "server", but packwiz has no per-file side flag
for non-metafile entries.

config/petprotect.json

@@ -0,0 +1,9 @@
+{
+  "prevent_pet_damage": false,
+  "only_prevent_players": false,
+  "prevent_pet_death": false,
+  "apply_totem_effects": false,
+  "prevent_pet_attack": true,
+  "allow_owner_damage": false,
+  "ignore_creative": true
+}