refactor: modular init, add bedrock loader, dynamic java/healthcheck

- Split monolithic init into modular lib files under scripts/lib/
  (common.sh, java.sh, server.sh, loaders/{vanilla,paper,fabric,forge,neoforge}.sh)
- Add bedrock loader: downloads from Minecraft Services API,
  runs native binary with LD_LIBRARY_PATH, skips Java setup
- Add auto-detection for JAVA_VERSION from Mojang version manifest
  (MC 1.20.5+ -> temurin@21, 1.17-1.20.4 -> temurin@17,
   1.17 -> temurin@16, pre-1.17 -> temurin@8)
- Fix NEW_FORGE unbound variable when non-Forge loaders run
- Fix Fabric loader jq filter (-s slurp removed, null string check fixed)
- Fix Forge test detection (recursive find for forge-*-server.jar)
- Dynamic healthcheck: nc -z TCP 25565 for Java, nc -zu UDP 19132 for bedrock
- Add .gitea/workflows/build-dev.yml for dev branch CI builds
- Base image: debian:bookworm-slim (from ubuntu:noble)
- Add unzip, netcat-openbsd to Docker image
- Switch to shebangs, set -euo pipefail throughout

scripts/lib/java.sh

@@ -0,0 +1,53 @@
+javaVersionDetect() {
+  if [[ -n "${JAVA_VERSION:-}" ]]; then
+    return
+  fi
+
+  local MANIFEST
+  MANIFEST=$(curl -sf "https://launchermeta.mojang.com/mc/game/version_manifest.json")
+  if [[ -z "$MANIFEST" ]]; then
+    JAVA_VERSION="temurin@21"
+    return
+  fi
+
+  local VERSION_URL
+  VERSION_URL=$(echo "$MANIFEST" | jq -r ".versions[] | select(.id == \"${MC_VERSION}\") | .url")
+  if [[ -z "$VERSION_URL" || "$VERSION_URL" == "null" ]]; then
+    JAVA_VERSION="temurin@21"
+    return
+  fi
+
+  local VERSION_DATA
+  VERSION_DATA=$(curl -sf "$VERSION_URL")
+  if [[ -z "$VERSION_DATA" ]]; then
+    JAVA_VERSION="temurin@21"
+    return
+  fi
+
+  local JAVA_MAJOR
+  JAVA_MAJOR=$(echo "$VERSION_DATA" | jq -r ".javaVersion.majorVersion // empty")
+  if [[ -z "$JAVA_MAJOR" ]]; then
+    JAVA_VERSION="temurin@8"
+  else
+    JAVA_VERSION="temurin@${JAVA_MAJOR}"
+  fi
+}
+
+javaCheck() {
+  javaVersionDetect
+
+  JAVA_HOME="/data/java/${JAVA_VERSION}"
+  if [[ -f "$HOME/.jabba/jabba.sh" ]]; then
+    source $HOME/.jabba/jabba.sh
+  else
+    echo "Something went wrong with locating jabba(the java installer)"
+    exit 1
+  fi
+
+  if [[ ! -f "/data/java/${JAVA_VERSION}/bin/java" ]]; then
+    rm -rf /data/java/${JAVA_VERSION}
+    jabba install ${JAVA_VERSION} -o /data/java/${JAVA_VERSION}
+  fi
+  PATH=${JAVA_HOME}/bin:$PATH
+  JAVA="java"
+}