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/lib/loaders/paper.sh

@@ -1,23 +1,59 @@
 getPaper() {
   SERVER_TYPE="Paper Minecraft"
-  if [[ ! -f server.jar ]]; then
-    if [[ -n "${PAPER_BUILD}" ]]; then
-      LATEST_BUILD="${PAPER_BUILD}"
-    else
-      LATEST_BUILD=$(curl -s https://api.papermc.io/v2/projects/${MC_LOADER}/versions/${MC_VERSION}/builds |
-        jq -r '[.builds[] | select(.channel | ascii_upcase == "STABLE")] | .[-1].build')
+
+  if [[ -z "${MC_VERSION}" ]]; then
+    die "MC_VERSION is required for Paper loader"
+  fi
+
+  if [[ -f server.jar ]]; then
+    log "Paper server.jar already exists, skipping download."
+    return
+  fi
+
+  local PAPERMC_URL
+
+  if [[ -n "${PAPER_BUILD}" ]]; then
+    log "Fetching Paper build ${PAPER_BUILD} for MC ${MC_VERSION}..."
+    local BUILD_DATA
+    BUILD_DATA=$(curl -sf --connect-timeout 10 --max-time 30 \
+      -H "User-Agent: dockercraft/1.0" \
+      "https://fill.papermc.io/v3/projects/paper/versions/${MC_VERSION}/builds") || true
+
+    if [[ -n "$BUILD_DATA" ]]; then
+      PAPERMC_URL=$(echo "$BUILD_DATA" | jq -r \
+        "map(select(.id == ${PAPER_BUILD})) | .[0].downloads.\"server:default\".url // empty")
     fi
 
-    if [ "$LATEST_BUILD" != "null" ]; then
-      JAR_NAME=${MC_LOADER}-${MC_VERSION}-${LATEST_BUILD}.jar
-      PAPERMC_URL="https://api.papermc.io/v2/projects/${MC_LOADER}/versions/${MC_VERSION}/builds/${LATEST_BUILD}/downloads/${JAR_NAME}"
+    if [[ -z "$PAPERMC_URL" ]]; then
+      die "Paper build ${PAPER_BUILD} not found for MC ${MC_VERSION}"
+    fi
+  else
+    log "Querying PaperMC API for latest stable build of ${MC_VERSION}..."
+    local BUILDS_DATA
+    BUILDS_DATA=$(curl -sf --connect-timeout 10 --max-time 30 \
+      -H "User-Agent: dockercraft/1.0" \
+      "https://fill.papermc.io/v3/projects/paper/versions/${MC_VERSION}/builds") || true
 
-      curl -o server.jar "$PAPERMC_URL"
-      echo "Download completed"
-      echo "Minecraft Version: ${MC_VERSION}"
-      echo "Paper Version: ${LATEST_BUILD}"
-    else
-      echo "No stable build for version $MC_VERSION found :("
+    if [[ -z "$BUILDS_DATA" ]]; then
+      die "Could not fetch Paper builds for MC ${MC_VERSION}"
+    fi
+
+    # Check for API error
+    if echo "$BUILDS_DATA" | jq -e '.ok == false' >/dev/null 2>&1; then
+      local ERR_MSG
+      ERR_MSG=$(echo "$BUILDS_DATA" | jq -r '.message // "Unknown error"')
+      die "PaperMC API error: ${ERR_MSG}"
+    fi
+
+    PAPERMC_URL=$(echo "$BUILDS_DATA" | jq -r \
+      'first(.[] | select(.channel == "STABLE") | .downloads."server:default".url) // empty')
+
+    if [[ -z "$PAPERMC_URL" ]]; then
+      die "No stable Paper build found for MC ${MC_VERSION}"
     fi
   fi
+
+  log "Downloading Paper for MC ${MC_VERSION}..."
+  curl -fL -o server.jar "$PAPERMC_URL"
+  log "Paper for MC ${MC_VERSION} downloaded."
 }