Release AnyLabeling v0.4.43

[vietanhdev]

Release scope

• contain model download/extraction/initialization failures without leaving Qt workers or UI stuck (Clean up model workers after download and load errors #262)
• skip invalid images during SAM preloading (fix: skip invalid images during SAM preload #264)
• persist grouped shapes across image changes and support undo (Fix grouped shapes disappearing after image changes #266)
• close label files deterministically for reliable overwrite/delete workflows (Close label files reliably after reads and writes #269)
• render the AnyLearning banner correctly in PyPI metadata (Fix the AnyLearning banner on PyPI #268)

Validation

• latest full suite on main: 142 passed, 13 optional-model tests skipped
• fresh-checkout sdist and wheel build passed twine check
• fresh wheel contains no build/cache artifacts and imports as version 0.4.43 in a clean no-deps environment
• wheel metadata contains the absolute, commit-pinned AnyLearning banner URL
• Close label files reliably after reads and writes #269 passed all 9 Linux/macOS/Windows jobs plus a physical Windows file-lock test

After merge I will tag v0.4.43, monitor CPU/GPU PyPI publishing and all six desktop builds, launch-test/checksum the assets, and normalize the release name/notes.