Phase 8: the pack's own JEI pages for every drop source

Adrian, 2026-11-02/03: every item that can drop gets a JEI page naming its
sources, alongside the Cobblemon Info add-on (which shows drops and biomes,
not zones). The companion mod's JEI plugin (jei/DropSourcesJei.kt) adds:
- Pokemon drops on the island: 794 species of lines that live on the
  island, with chances, amounts and the zones they spawn in (or where their
  line lives); spawns with their own drops (Beheeyem in the End). The Drop
  Synthesizer core is the catalyst.
- Guardians and the End boss; Sacrifice Altar tiers and specials; Rebirth
  Chamber; zone ore veins with regrow times; Cobblebase pasture finds per
  skill and zone.

JEI runs on the client, so the pages read assets/cobblesurvival/jei/
drop_sources.json inside the mod, written by tools/jei_sources.py from the
pack's files. Self-tests drop_sources_match_the_server (file vs live server:
drops, zones, own-drop spawns, guardians, End boss, altar) and
jei_pages_build (every page builds, every item exists). The ore a vein gives
moved into world/zones.json (ores -> item), shared with the quest book.
JEI's API (19.64.0.455) is a compile-only dependency from JEI's own Maven.
Self-tests and the island check pass.

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

docs/design.md

@@ -311,7 +311,14 @@ Adrian's choices: Cobblemon tasks come from **Cobblemon Quests Reloaded** (a mai
 - **Node positions:** Adrian moves nodes in the in-game editor; `tools/quests.py --pull <folder>` records every node that isn't where the generator would put it in the `layout` block at the end of `docs/quests.yaml`. `tools/prism_instance.py` does that from the instance before each sync, and rebuilds if something moved, so a sync never undoes his layout (docs/quests.yaml then needs committing). Titles, texts, tasks and dependencies edited in game are overwritten.
 - **Self-tests:** `quest_book_loads` (FTB Quests on the server has the book in flexible mode, every task type is known, every item and advancement exists), `quest_events_mark_zones`, and the guardian and furnace tests check their events.
 - Still open: the flexible-mode soft-lock a fix mod reports for 1.20.1 (tasks done before their dependencies); checked in game for now.
-- JEI (next): our plugin adds, per item, every place on the island it comes from that Cobblemon Info doesn't cover: guardian and End boss rewards, Sacrifice Altar tiers, ore veins by zone, pasture mining and finder tables by zone; and per Pokémon its zone.
+**Drop sources in JEI** (Adrian, 2026-11-02/03). The companion mod adds its own JEI pages (`jei/DropSourcesJei.kt`); look an item up (its recipes) to see every place on the island it comes from:
+- **Pokémon drops on the island:** one page per species of a line that lives on the island (794): its drops with chance and amount, the zones it spawns in with their levels, or for a form that isn't wild, where its line lives ("Not wild; its line lives in Westmarch (Pichu)"). The Drop Synthesizer core is the page's catalyst (it rolls the same drops). Spawns with drops of their own get a page too (Beheeyem in the End: ender pearls). This is the zone information the Cobblemon Info add-on can't show.
+- **Guardians and the End boss:** each guardian's species, level, zone, drops and return time; Eternatus with its experience and the dragon egg on the first win.
+- **Sacrifice Altar** (each level tier and the Dragon-type special) and **Rebirth Chamber** (the Ability Patch), with their cores as catalysts.
+- **Zone ore veins:** per zone, what its veins give and how fast they regrow.
+- **Pasture finds:** per Cobblebase skill (mining, ore finder, evolution-item finder) and zone, what a pastured Pokémon can find there; the Pasture Block is the catalyst.
+
+JEI runs on the client, which on a dedicated server doesn't have the server's data, so the pages are built from `assets/cobblesurvival/jei/drop_sources.json` inside the mod, written by `tools/jei_sources.py` from the pack's own files (Cobblemon's species drops with the pack's species additions, the zone spawn pools, guardians, the End boss, the machines, `world/zones.json` ores, Cobblebase's zone tables). Which ore a vein gives now lives in `world/zones.json` → `ores` → `item` (the quest book reads it too). Self-tests: `drop_sources_match_the_server` compares the file with the live server (every listed Pokémon's drops and zones, spawns with own drops, guardians, the End boss, altar tiers) and fails when it's stale; `jei_pages_build` builds every page with the same code JEI calls and checks every item exists.
 
 ## Open decisions for Adrian (proceeding with the default, flagged)