feat(config): moderate spawn tuning for Alex's Mobs, Fowl Play, Critters

Every visible entity multiplies the client render cost (vanilla, EMF/FA,
GeckoLib, ETF, dynamic lights) and the server tick. These cuts target only the
species that are heavy by weight x group size. Rare mobs keep their defaults.

- Alex's Mobs: halve 9 common weights (gazelle and capuchin herds, straddler,
  rocky roller, underminer, elephant, blobfish, mudskipper, caiman).
- Fowl Play: lower duck/goose/gull/sparrow weights and max group sizes
  (upstream #214, ~400 ducks on rivers, is still open in 1.2.3).
- Critters and Companions: about 40% off sea bunnies and the forest/lush bug
  rules. It does have a spawn config; configVersion 2 skips its v1->v2
  migration.

All three are partial files. NeoForge (TOML) and YACL 3.8.2 (JSON5) keep
defaults for missing keys. Shipped enforced from config/ because the server
reads them from this repo. Details and the B14 measurement plan:
analysis/client-perf/SPAWN-TUNING.md.

index.toml

@@ -4,6 +4,14 @@ hash-format = "sha256"
 file = "config/akashictome-common.toml"
 hash = "4e479c86ddfec0c5e28f07034f033a10abae404309f38ccc4bfc15da9de2dfa2"
 
+[[files]]
+file = "config/alexsmobs-common.toml"
+hash = "bc47ee67032ceab8b2b408819ce9b268812f37da8f13b9b7efeae0deed607c4b"
+
+[[files]]
+file = "config/crittersandcompanions-common.json5"
+hash = "a00a9fe09ce5b469247f757e780b5faf74191f5cfef158d999c4d7a1e203f420"
+
 [[files]]
 file = "config/defaultoptions/extra/config/DistantHorizons.toml"
 hash = "8949bf3c7a43df7a7ae384213db0985425db3559219c29cb63eaef45c7962dcc"
@@ -36,6 +44,10 @@ hash = "9b75828543ed2b8cc5804eabecdc28262297a90d6f0e8e771d64ff779a69e3c9"
 file = "config/defaultoptions/options.txt"
 hash = "62034e0589087dab02d1a15192ad313a57f907d5ee9ebbf8853151f7831851a1"
 
+[[files]]
+file = "config/fowlplay.json5"
+hash = "09ad767a358310e9d38e632ba0e670b0afd1554c162eadb6928d106df17b66c3"
+
 [[files]]
 file = "config/paxi/datapacks/onion-fixes/data/adorablehamsterpets/recipe/cucumber_crate.json"
 hash = "21b11674b18c3fb0d8292095cf7c12bca82ef4054ec3f1cd8d1e0222d1655629"