Phase 4: regenerating ore veins, each tier in one zone

Regenerating Ore Veins 1.4.0 (CurseForge only, MIT). tools/zone_ores.py
writes its config from world/zones.json: surface zones as boxes from the
zone grid, cave tiers by cave biome, 21 tiers including Cobblemon's
evolution stones (their natural ores are off). The world report now
allows ore only in tracked veins inside their tier's zone. Self-tests:
a mined vein regrows after its chunk unloads and after a restart (new
after_restart pass in selftest.py and quick_check.py). make_world places
showcase veins.

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

pack/mods/regenerating-ore-veins.pw.toml

@@ -0,0 +1,13 @@
+name = "Regenerating Ore Veins"
+filename = "regenerating_ore_veins-neoforge-1.21.1-1.4.0.jar"
+side = "both"
+
+[download]
+hash-format = "sha1"
+hash = "cb1edab284593a48d0b0ee22614c0f786d427158"
+mode = "metadata:curseforge"
+
+[update]
+[update.curseforge]
+file-id = 8066055
+project-id = 1535476