Implemented arbitrary positioning support in compressed WAL files. WAL segments are now fully loaded into memory to enable efficient validation and other operations with compressed files.

Fixed an issue that caused assertion error and crash when attempting to create a directory that already exists.

Changed the --batch-size default behavior to fix multithreading issue. When unspecified, --batch-size now defaults to the -j/--threads value instead of the previous 1.

Optimized memory usage when creating file maps to prevent memory exhaustion for the --with-file-map and file-map operations.