ci(test): use preflight/guard pattern to show skipped steps as grey

Replace the exit-77 + set+e wrapper with a preflight step that writes
can_run and skip_reason to GITHUB_OUTPUT. The test step is guarded by
if: steps.<id>.outputs.can_run == 'true', so it shows as grey Skipped
(not green Success) when prerequisites are missing.

The Store preflight distinguishes 'missing tool: <name>' from
'ulimit -n is <N> (store requires >= 1024)' with separate skip_reason
values as requested in review.

Addresses blocking review feedback from imbajin on #3055.
Related to: #3043

Author: bitflicker64

.github/workflows/pd-store-ci.yml

@@ -107,19 +107,29 @@ jobs:
         run: |
           mvn clean package -U -Dmaven.javadoc.skip=true -Dmaven.test.skip=true -ntp --fail-at-end
 
+      - name: Check startup test prerequisites (PD)
+        id: pd-preflight
+        run: |
+          for tool in lsof curl java; do
+            if ! command -v "$tool" >/dev/null 2>&1; then
+              echo "can_run=false" >> "$GITHUB_OUTPUT"
+              echo "skip_reason=missing tool: $tool" >> "$GITHUB_OUTPUT"
+              exit 0
+            fi
+          done
+          echo "can_run=true" >> "$GITHUB_OUTPUT"
+
       - name: Run start-hugegraph-pd.sh foreground mode tests
+        if: steps.pd-preflight.outputs.can_run == 'true'
         run: |
           VERSION=$(mvn help:evaluate -Dexpression=project.version -q -DforceStdout)
           PD_DIR=hugegraph-pd/apache-hugegraph-pd-$VERSION/
-          set +e
           $TRAVIS_DIR/test-start-hugegraph-pd.sh $PD_DIR
-          EXIT=$?
-          set -e
-          if [ $EXIT -eq 77 ]; then
-            echo "::notice::PD startup tests skipped — required tools not available"
-            exit 0
-          fi
-          exit $EXIT
+
+      - name: Startup tests skipped (missing prerequisites)
+        if: steps.pd-preflight.outputs.can_run == 'false'
+        run: |
+          echo "::notice::PD startup tests skipped — ${{ steps.pd-preflight.outputs.skip_reason }}"
 
       - name: Prepare env and service
         run: |
@@ -177,19 +187,35 @@ jobs:
         run: |
           mvn clean package -U -Dmaven.javadoc.skip=true -Dmaven.test.skip=true -ntp --fail-at-end
 
+      - name: Check startup test prerequisites (Store)
+        id: store-preflight
+        run: |
+          for tool in lsof curl java; do
+            if ! command -v "$tool" >/dev/null 2>&1; then
+              echo "can_run=false" >> "$GITHUB_OUTPUT"
+              echo "skip_reason=missing tool: $tool" >> "$GITHUB_OUTPUT"
+              exit 0
+            fi
+          done
+          LIMIT_N=$(ulimit -n)
+          if [[ "$LIMIT_N" != "unlimited" ]] && (( LIMIT_N < 1024 )); then
+            echo "can_run=false" >> "$GITHUB_OUTPUT"
+            echo "skip_reason=ulimit -n is $LIMIT_N (store requires >= 1024)" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          echo "can_run=true" >> "$GITHUB_OUTPUT"
+
       - name: Run start-hugegraph-store.sh foreground mode tests
+        if: steps.store-preflight.outputs.can_run == 'true'
         run: |
           VERSION=$(mvn help:evaluate -Dexpression=project.version -q -DforceStdout)
           STORE_DIR=hugegraph-store/apache-hugegraph-store-$VERSION/
-          set +e
           $TRAVIS_DIR/test-start-hugegraph-store.sh $STORE_DIR
-          EXIT=$?
-          set -e
-          if [ $EXIT -eq 77 ]; then
-            echo "::notice::Store startup tests skipped — required tools not available"
-            exit 0
-          fi
-          exit $EXIT
+
+      - name: Startup tests skipped (missing prerequisites)
+        if: steps.store-preflight.outputs.can_run == 'false'
+        run: |
+          echo "::notice::Store startup tests skipped — ${{ steps.store-preflight.outputs.skip_reason }}"
 
       - name: Prepare env and service
         run: |

.github/workflows/server-ci.yml

@@ -70,21 +70,31 @@ jobs:
         run: |
           mvn clean compile -U -Dmaven.javadoc.skip=true -ntp
 
-      - name: Run start-hugegraph.sh foreground mode tests
+      - name: Check startup test prerequisites
+        id: server-preflight
         if: ${{ env.BACKEND == 'rocksdb' }}
+        run: |
+          for tool in lsof crontab curl java; do
+            if ! command -v "$tool" >/dev/null 2>&1; then
+              echo "can_run=false" >> "$GITHUB_OUTPUT"
+              echo "skip_reason=missing tool: $tool" >> "$GITHUB_OUTPUT"
+              exit 0
+            fi
+          done
+          echo "can_run=true" >> "$GITHUB_OUTPUT"
+
+      - name: Run start-hugegraph.sh foreground mode tests
+        if: ${{ env.BACKEND == 'rocksdb' && steps.server-preflight.outputs.can_run == 'true' }}
         run: |
           mvn package -Dmaven.test.skip=true -pl hugegraph-server/hugegraph-dist -am -ntp
           VERSION=$(mvn help:evaluate -Dexpression=project.version -q -DforceStdout)
           SERVER_DIR=hugegraph-server/apache-hugegraph-server-$VERSION/
-          set +e
           $TRAVIS_DIR/test-start-hugegraph.sh $SERVER_DIR
-          EXIT=$?
-          set -e
-          if [ $EXIT -eq 77 ]; then
-            echo "::notice::Startup tests skipped — required tools not available"
-            exit 0
-          fi
-          exit $EXIT
+
+      - name: Startup tests skipped (missing prerequisites)
+        if: ${{ env.BACKEND == 'rocksdb' && steps.server-preflight.outputs.can_run == 'false' }}
+        run: |
+          echo "::notice::Server startup tests skipped — ${{ steps.server-preflight.outputs.skip_reason }}"
 
       - name: Run unit test
         run: |