[Marouane-elfadli]

What does this change?

Adds 10 new file formats and 2 small features, each linked to its issue where there is one:

• .mermaid / .mmd are read as plain text, like other code files. Fixes [Format]: .mermaid #1309
• .udf disc images are unpacked with 7-Zip (read only, like ISO/IMG). Fixes [Format]: .udf #1338
• Rust, Go, Kotlin, Swift, Scala, SCSS, Vue and TSX sources (.rs, .go, .kt, .swift, .scala, .scss, .vue, .tsx) are read as plain text, the same way .java was added in [Format]: .java #1176. No issue.
• Feature: .m4r iPhone ringtone output (AAC in the iPod muxer; ALAC is not offered, since iOS does not play it). Fixes [Feature]: Add iPhone ringtone (M4R) conversion #1291
• Feature: Ukrainian as a target language of the Translator (Ollama). Fixes [Feature]: Add Ukrainian (Українська) as a target language for the Translator (Ollama) engine #1344

Libraries saved by an older Filee learn the new extensions through a settings migration (schema 77). Donuts with custom claims on an extension keep them.

Not included on purpose: .js, .php and shell scripts (programs and web pages, refused by WebFileNames), and .djvu (needs a separate engine).

Type of change

• Bug fix
• New feature or improvement
• New format or engine
• Translation
• Documentation
• Build, CI or dependencies

How was it tested?

• dotnet format --verify-no-changes
• dotnet test
• Tried it in the app (what you converted or clicked, and on which OS):

Tests added or updated:

• tests/Filee.Core.Tests/ScriptTextTests.cs: detection of the new extensions, UDF and M4R recognition, and the schema 76 → 77 migration (custom claims are kept).
• tests/Filee.Core.Tests/FormatFieldsTests.cs: grade counts (UDF and M4R are graded General, like ISO and M4B).
• tests/Filee.Engines.Tests/ScriptTextTests.cs: Mermaid, Rust and Go files convert to PDF.
• tests/Filee.Engines.Tests/ArchiveTests.cs: UDF has a one-step route to every archive target.
• tests/Filee.Engines.Tests/MediaTests.cs: M4R is always AAC in the iPod muxer, even when ALAC is asked for.

Screenshots (UI changes)

None. The only UI change is one more entry (Українська) in the Translate language list.

Checklist

• New UI strings are in all src/Filee.App/Assets/i18n/*.json files (no new keys; the language name is written in its own language, like the others)
• New third-party code or binaries are listed in THIRD-PARTY-NOTICES.md (none added)
• The PR does one thing (unrelated changes go in a separate PR)

Several small changes that share FormatRegistry.cs and the settings migration. They can be split into separate PRs if you prefer.