refactor(data): swap PointValueJob buffer outside the write lock

The quartz-driven batch flush used to hold VALUE_LOCK.writeLock() across
the whole save — receiver threads calling addPointValues() stalled behind
DB I/O whenever a flush was in flight, throttling ingest under load.

The new flow snapshots POINT_VALUE_LIST into a private ArrayList under the
lock, clears the shared buffer, releases the lock, then runs save() on the
snapshot in a virtual thread. The lock window is now just a list copy plus
a clear.

Also: PointValueReceiver's enqueue path now wraps lock/unlock in try-
finally so an unexpected addPointValues() exception cannot leak the lock.

dc3-common/dc3-common-data/src/main/java/io/github/pnoker/common/data/job/PointValueJob.java

@@ -92,14 +92,21 @@ public class PointValueJob extends QuartzJobBean {
             log.debug("Point value receiver speed: {} /s, value size: {}, interval: {}", speed, getPointValuesSize(), interval);
         }
 
-        // Save point value array to Redis & PostgreSQL
-        virtualThreadExecutor.execute(() -> {
-            VALUE_LOCK.writeLock().lock();
-            if (!POINT_VALUE_LIST.isEmpty()) {
-                pointValueService.save(POINT_VALUE_LIST);
-                clearPointValues();
+        // Swap out the accumulated buffer under the lock; run the save on a private
+        // snapshot outside the lock so concurrent addPointValues callers are not blocked
+        // by DB I/O.
+        List<PointValueBO> snapshot;
+        VALUE_LOCK.writeLock().lock();
+        try {
+            if (POINT_VALUE_LIST.isEmpty()) {
+                return;
             }
+            snapshot = new ArrayList<>(POINT_VALUE_LIST);
+            POINT_VALUE_LIST.clear();
+        } finally {
             VALUE_LOCK.writeLock().unlock();
-        });
+        }
+
+        virtualThreadExecutor.execute(() -> pointValueService.save(snapshot));
     }
 }

dc3-common/dc3-common-data/src/main/java/io/github/pnoker/common/data/rabbit/PointValueReceiver.java

@@ -75,8 +75,11 @@ public class PointValueReceiver {
             } else {
                 // Save point value to schedule
                 PointValueJob.VALUE_LOCK.writeLock().lock();
-                PointValueJob.addPointValues(pointValueBO);
-                PointValueJob.VALUE_LOCK.writeLock().unlock();
+                try {
+                    PointValueJob.addPointValues(pointValueBO);
+                } finally {
+                    PointValueJob.VALUE_LOCK.writeLock().unlock();
+                }
             }
         } catch (Exception e) {
             log.error(e.getMessage(), e);