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>

docs/roadmap.md

@@ -193,6 +193,8 @@ Goal: a quest book that points players onward, laid out like a research tree who
 - **Every implemented Pokémon is obtainable** (Adrian, 2026-11-09). Every species Cobblemon has a model for must be reachable somewhere in the world, even if rarely or through crafting: a wild spawn, evolving a wild line, a fossil, or a crafted or summoned encounter. Legendaries and the like count too; they can be very rare or expensive. Checked on 2026-11-09: 95 of 905 implemented species are not reachable by a wild spawn or by evolving a wild line (legendaries, fossils, and lines the zone assignment left out, such as Aron, Litwick and Piplup). Report what is missing with a tool or self-test so new Cobblemon versions can't reopen the gap.
 - **A shader pack included** (Adrian, 2026-11-09). Ship [Iris](https://modrinth.com/mod/iris) (client only) and [Complementary Reimagined](https://modrinth.com/shader/complementary-reimagined), installed but off by default; players switch it on with a key or in Video Settings. Iris 1.8.14-beta.1+1.21.1-neoforge (MR `KduFYu4t`) is built against Sodium 0.8.13, which the pack already pins; it is the only NeoForge 1.21.1 build for Sodium 0.8, and a beta. Complementary r5.9.3 (MR `Bqen1mJX`) has the most downloads of the common shader packs and keeps a vanilla-like look, which suits Cobblemon's models. Its license allows modpacks if it is left unmodified, credited where the pack is described when it's on by default (it isn't; it's credited anyway), and added through Modrinth or CurseForge's own systems, never as an uploaded file: the private pack has to download it from Modrinth. Check that Cobblemon's models, the machine and boss particles and the see-through blocks render properly with it on, and measure the frame-rate cost.
 - **Performance.** Profile with spark on a server with realistic pen and machine counts; cap entity density through pasture config if needed.
+- **Reproducible builds** (Adrian, 2026-11-09). The same commit gives the same bytes: pinned JDK, packwiz, Gradle plugins and Python packages; `tools/check_reproducible.py` proves it.
+- **Balancing on the server** (Adrian, 2026-11-09). Balance changes reach playtesters without a client update: `tools/server_update.py`, a server-held data pack, JEI pages sent by the server.
 - **Multiplayer test** with Adrian's group.
 - **Release.** Final `docs/licenses.md`, credits and non-affiliation disclaimer; publish client and server packs on Modrinth and CurseForge as dependency-based packs.