fix: migrate PaperMC to v3 API, fix NeoForge beta fallback, add test suite

- Migrate Paper loader from sunset v2 API to v3 (fill.papermc.io)
- Fix NeoForge: fall back to beta versions when no stable exists (set -e + grep)
- Fix setEula/setperms ordering (was writing eula.txt before /data was writable)
- Fix setEula/serverInfoWrite to use absolute paths (/data/server/)
- Add VOLUME directive removal (was shadowing bind mounts)
- Add comprehensive API test suite (110 tests across 6 suites)
- Move test.sh to tests/integration.sh, switch to named volumes
- Add Docker build cache to CI workflows
- Add .editorconfig, expand .gitignore, improve README docs

scripts/init

@@ -1,49 +1,81 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-MC_VERSION=${MC_VERSION:-}
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-MC_LOADER=${MC_LOADER:-}
-MC_LOADER_VERSION=${MC_LOADER_VERSION:-}
+# ---------- source helpers first (so log/die are available) ----------------
+# shellcheck disable=SC1091
+source "${SCRIPT_DIR}/lib/common.sh"
 
-FABRIC_LOADER_VERSION=${FABRIC_LOADER_VERSION:-${MC_LOADER_VERSION:-}}
-FORGE_VERSION=${FORGE_VERSION:-${MC_LOADER_VERSION:-}}
-NEOFORGE_VERSION=${NEOFORGE_VERSION:-${MC_LOADER_VERSION:-}}
-PAPER_BUILD=${PAPER_BUILD:-""}
+# ---------- environment variables ------------------------------------------
 
-JAVA_VERSION=${JAVA_VERSION:-}
-JAVA_HOME=/data/java/${JAVA_VERSION}
-JAR=${JAR:-"server.jar"}
+MC_VERSION="${MC_VERSION:-}"
+MC_LOADER="${MC_LOADER:-}"
+MC_LOADER_VERSION="${MC_LOADER_VERSION:-}"
 
-XMS=${XMS:-2G}
-XMX=${XMX:-4G}
+FABRIC_LOADER_VERSION="${FABRIC_LOADER_VERSION:-${MC_LOADER_VERSION:-}}"
+FORGE_VERSION="${FORGE_VERSION:-${MC_LOADER_VERSION:-}}"
+NEOFORGE_VERSION="${NEOFORGE_VERSION:-${MC_LOADER_VERSION:-}}"
+PAPER_BUILD="${PAPER_BUILD:-}"
 
-ADD_ARGS=${ADD_ARGS:-""}
+JAVA_VERSION="${JAVA_VERSION:-}"
+JAVA_HOME="/data/java/${JAVA_VERSION}"
+JAR="${JAR:-server.jar}"
+
+XMS="${XMS:-2G}"
+XMX="${XMX:-4G}"
+
+ADD_ARGS="${ADD_ARGS:-}"
 
 PUID="${PUID:-1000}"
 PGID="${PGID:-1000}"
 
-PATH=${JAVA_HOME}/bin:$PATH
+PATH="${JAVA_HOME}/bin:$PATH"
 
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# ---------- validate required vars early -----------------------------------
 
-source "${SCRIPT_DIR}/lib/common.sh"
+if [[ -z "$MC_LOADER" ]]; then
+  die "MC_LOADER is required. Valid: vanilla, paper, fabric, forge, neoforge, bedrock"
+fi
+
+if [[ "$MC_LOADER" != "bedrock" ]]; then
+  if [[ -z "$MC_VERSION" ]]; then
+    die "MC_VERSION is required for ${MC_LOADER} loader"
+  fi
+fi
+
+# ---------- source libraries ------------------------------------------------
+
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/java.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/server.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/loaders/vanilla.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/loaders/paper.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/loaders/fabric.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/loaders/forge.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/loaders/neoforge.sh"
+# shellcheck disable=SC1091
 source "${SCRIPT_DIR}/lib/loaders/bedrock.sh"
 
+# ---------- main flow -------------------------------------------------------
+
 setperms
+setEula
+
 if [[ "$MC_LOADER" != "bedrock" ]]; then
   javaCheck
 fi
+
 serverSelect
+
 if [[ "$MC_LOADER" != "bedrock" ]]; then
   buildCommand
 fi
-setEula
+
 serverStart