feat: Unreal Engine support - One File Per Actor filename decoding

[Jus2Cat]

This PR adds support for Unreal Engine's One File Per Actor system. It decodes hashe filenames
(e.g. KCBX0GWLTFQT9RJ8M1LY8.uasset) into human-readable view.

This solves a major pain point for UE developers where file names are meaningless hash strings.

This makes it impossible to identify which actors have been modified without opening the Unreal Editor, causing significant workflow delays.
Currently, only one paid Git client offers a similar feature, and there are no free alternatives.

🛡️ Safety & Performance (Key Highlights)

• Zero Overhead by Default: The feature is completely opt-in. All heavy logic is guarded by
  EnableUnrealEngineSupport. If disabled, this code path is never executed.
• Memory Safe: Binary decoding is capped at 256KB per file. This prevents
  System.OutOfMemoryException and UI freezes, even if users modify huge binary assets (1GB+).
• Batched Processing: Instead of spawning a process for every file, it uses git cat-file --batch
  to read Git objects. This makes it performant even with thousands of changes.
• Caching: Decoded names are cached based on file size/timestamp to avoid redundant I/O on
  refresh.

🛠️ Changes

1. Core: Added OFPAParser (custom binary reader for .uasset headers).
2. ViewModel: Integrated async decoding into WorkingCopy.cs using Task.Run to keep UI responsive.
3. UI: Added toggle in Repository Settings and Working Copy toolbar. Added specific icons for
   decoded files.
4. Tests: Added comprehensive unit tests covering Parser edge cases and UI Converters.
5. Locales: Added translations for English, Russian, and Chinese (Simplified).

• Full View Support: Works across all three display modes: Tree, List, and Grid.
• The feature is active only within Unreal Engine projects containing __ExternalActors__ or __ExternalObjects__ folders and a .uproject file.
• Zero Clutter: For non-Unreal repositories, the OFPA toggle and icons are not displayed,
  ensuring no impact on the standard Git workflow.

[redsigma]

does the decoding also allow to show if the file is locked by someone ? It would be nice if it name shows
<actor name> - <locked by PersonX>

I think it would be useful to have that if possible

[Jus2Cat]

does the decoding also allow to show if the file is locked by someone ? It would be nice if it name shows <actor name> - <locked by PersonX>

I think it would be useful to have that if possible

Updated.

[redsigma]

@Jus2Cat Awesome work with this PR . I see you added a button to view the locked files in a separate window. I think this approach might be difficult to use if you have 50 locked files and you have to figure out which person locked it.

Would it be possible maybe to achieve one of the following:

1. Locked files show with a different icon. Currently there is green (added), red(removed) , orange(modified). Maybe some icon like blue can be added ?

2. Have the locked files be hidden from the commit list. And have a separate button to show them as well.

3. Have separate button which checks every file in the staging, and lists the locked files and who has locked them.

[pabermod]

If File lock is independent from this functionality (And usable for other file type) I think is better to not mix it and do it in another PR?

Regards

[Jus2Cat]

Hi! I've rebased and significantly cleaned up this PR:

What changed:

• Rebased onto latest develop
• Removed unrelated changes (LFS locks, QueryFileContent, extra locales) — as suggested by @pabermod
• Extracted OFPADecodingContext to eliminate ~250 lines of duplication across ViewModels
• Added fallback to index/HEAD when working tree decode fails
• Follows project code style conventions
• Single checkbox in Repository Configuration instead of a separate section

Why this is safe to merge:

• Zero overhead when disabled — all decode logic is behind an opt-in per-repo toggle, no code paths are hit for non-UE repos
• No UI clutter — just one checkbox in settings, no extra UI when disabled
• Safety — binary reads capped at 256KB, batched via git cat-file --batch, async with stale-guard
• Tested — unit tests for parser across UE 5.3 / 5.6 / 5.7 formats

This solves a real pain point for Unreal Engine developers: OFPA generates opaque hash-based filenames that make it impossible to identify which actors changed without opening the editor. Currently no free Git client offers this.

Happy to split, simplify, or adjust anything. Would appreciate feedback on what would make this easier to review.

[Jus2Cat]

[Repository] to manually test the feature (no Unreal Engine needed):

The repo has 4 commits with ~210 OFPA files, including additions and deletions — enough to test all views (Local Changes, History, Stashes).