Refactor MerkleTree configuration for improved memory management and performance optimization

Author: EAOE3

src/main/java/io/pwrlabs/database/rocksdb/MerkleTree.java

@@ -100,7 +100,7 @@ public MerkleTree(String treeName) throws RocksDBException {
                 .setCreateIfMissing(true)
                 .setCreateMissingColumnFamilies(true)
                 .setUseDirectReads(true)
-                .setAllowMmapReads(true)
+                .setAllowMmapReads(false)
                 .setUseDirectIoForFlushAndCompaction(true)
                 .setMaxOpenFiles(100)
                 .setMaxBackgroundJobs(1)