Phase 9: reproducible builds, balance from the server, spark check, play feedback

Build: every tool pinned (JDK, packwiz, Gradle plugins, Python packages), exports
normalised, tools/check_reproducible.py proves two clean builds are byte-identical.

Server-side balance: a server can load config/cobblesurvival/datapack.zip in place of
the jar's data, /reload applies it, tools/server_update.py packages it and refuses
when a client change is needed. JEI drop pages are sent by the server. Code-held
balance numbers moved to tuning/server.json.

Performance: spark in the pack (server only), tools/perf_test.py with fake players
whose chunks really are active, docs/performance.md.

Adrian's feedback: default keys R, U, J, §; drop pages link to Cobblemon Info and show
real chances; bosses only hurt in battles; battle XP halved; channels between the
islands low level; temperature ×3 with insulation doubled; hazards start at once; no
item dots on the map; a wild attack starts a battle; the starter only faints; quest
book on join with a basics page and an HMs page; regional forms obtainable.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

world/summons.json

@@ -27,6 +27,9 @@
     "regigigas": {"zone": "deep_dark", "tier": 2, "material": "minecraft:echo_shard"},
     "rayquaza": {"zone": "frostpeak", "tier": 3, "material": "minecraft:emerald_block"},
     "mewtwo": {"zone": "deep_dark", "tier": 3, "material": "cobblemon:dusk_stone"},
-    "eternatus": {"zone": "the_end", "tier": 3, "material": "minecraft:ender_eye"}
+    "eternatus": {"zone": "the_end", "tier": 3, "material": "minecraft:ender_eye"},
+    "zapdos_galarian": {"species": "zapdos", "form": "galarian", "zone": "jungle", "tier": 2, "material": "cobblemon:thunder_stone"},
+    "articuno_galarian": {"species": "articuno", "form": "galarian", "zone": "highlands", "tier": 2, "material": "cobblemon:ice_stone"},
+    "moltres_galarian": {"species": "moltres", "form": "galarian", "zone": "deep_dark", "tier": 2, "material": "cobblemon:fire_stone"}
   }
 }