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>

tools/check_keybinds.py

@@ -20,6 +20,8 @@ from pathlib import Path
 
 ROOT = Path(__file__).resolve().parent.parent
 DEFAULTS = ROOT / "pack/config/defaultoptions/keybindings.txt"
+# Share a key on purpose (Adrian, 2026-11-09): JEI's only works in a screen, Cobblemon's sends out a Pokémon in the world.
+BY_DESIGN = [{"key.jei.showRecipe", "key.cobblemon.throwpartypokemon"}]
 INSTANCE = (Path.home() / ".var/app/org.prismlauncher.PrismLauncher/data/PrismLauncher/instances"
             / "Cobblemon Survival Pack (dev)/minecraft/options.txt")
 
@@ -52,6 +54,8 @@ def main():
     def clashes(entries):
         # One mod's binds share a context, so distinct modifiers keep them apart (e.g. JEI's
         # Page Down and Shift+Page Down). Anything else on the same key shows as a conflict.
+        if {name for name, _ in entries} in BY_DESIGN:
+            return False
         mods = {name.rsplit(".", 1)[0] for name, _ in entries}
         return len(entries) > 1 and not (len(mods) == 1 and len({m for _, m in entries}) == len(entries))