MKV Muxing Batch GUI 2.7.2

MKV Muxing Batch GUI 2.7.2

This maintenance release focuses on correctness and source-file safety while
bringing the abandoned original project onto the maintained 2.7.x codebase.

Highlights

• Failed MKVToolNix processes can no longer be reported as successful.
• Source replacement validates a non-empty completed output and publishes it
  atomically before the original file is removed.
• CRC renaming now follows the actual completed output path.
• Large queue cleanup no longer double-frees items or stalls UI updates.
• Discard Old Chapters and Discard Old Attachments work independently.
• Fast Mux state no longer leaks into later queue items.
• Current system MKVToolNix tools are preferred over stale bundled copies.
• Runtime/build dependencies are updated and pinned: PySide6 6.11.2,
  psutil 7.2.2, comtypes 1.4.16, and PyInstaller 6.22.2.

See CHANGELOG.md
for the complete list, and
docs/UPSTREAM_ISSUES.md
for the audited original-project issue snapshot.

Downloads

The attached x86-64 Linux one-folder archive was built and smoke-tested on
Linux. Install your distribution's mkvtoolnix and libxcb-cursor0 packages
before running it. Verify it with the attached SHA256SUMS.txt.

GitHub also supplies source archives automatically. Windows packaging metadata
and scripts are versioned for 2.7.2, but Windows binaries are not attached to
this release because they could not be built and validated on a Windows host.