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>

tools/selftest.py

@@ -1,6 +1,8 @@
 #!/usr/bin/env python3
 """Run the companion mod's in-game tests on their own: one server boot on a fresh flat
-world, `/cobblesurvival selftest run`, wait for the results, stop, scan the log.
+world, `/cobblesurvival selftest run`, wait for the results, stop, scan the log; then boot
+the world again for the second halves of the tests that span a restart
+(`/cobblesurvival selftest run after_restart`).
 
 The tests (mod/src/main/kotlin/dev/cobblesurvival/selftest/) play real situations on the
 live server with every mod and config of the pack, e.g. the permadeath matrix: Pokémon
@@ -47,6 +49,14 @@ def main():
         except Exception as e:  # report; the context manager still kills the process
             failures.append(f"{type(e).__name__}: {e}")
     failures += [f"log: {line}" for line in scan_log(server.log)]
+    with Server(args_file, props, stdout_name="selftest-restart-stdout.log", jvm_args=SELFTEST_JVM_ARGS) as server:
+        try:
+            print(f"server restarted in {server.wait_ready():.0f}s")
+            failures += server.run_selftest(after_restart=True)
+            server.stop()
+        except Exception as e:  # report; the context manager still kills the process
+            failures.append(f"{type(e).__name__}: {e}")
+    failures += [f"log after restart: {line}" for line in scan_log(server.log)]
     print(f"\nselftest took {time.time() - started:.0f}s")
     if failures:
         print("SELFTEST FAILED")