Standardise ChestShop's shaded jar name to chestshop-$version.jar

ChestShop's shadowJar hard-codes archiveBaseName=ChestShop and archiveVersion="", producing ChestShop.jar — out of step with the other plugins (treasury-2.3.0-SNAPSHOT.jar, etc.). The root release task therefore bundles a differently-named artifact.

Fix: drop the archiveBaseName/archiveVersion overrides so the jar defaults to chestshop-<version>.jar, using the pinned monorepo version inherited from the root allprojects block (2.3.0-SNAPSHOT / -Pversion) — matching the other three plugins. Keep archiveClassifier="".

No CI workflow or deploy script references the literal ChestShop.jar filename (Paper resolves the plugin by plugin.yml name, not the jar name). Docs that mention the filename (README, wiki, settings/root-build comments) updated to match.