[Marouane-elfadli]

What does this change?

Adds 10 new file formats and 2 small features. Each one is tagged with its issue where there is one.

Formats (label: formats)

Tag	Issue	What it does
[Format]: .mermaid	Fixes #1309	.mermaid and .mmd diagram files are read as plain text and can be converted like other text files.
[Format]: .udf	Fixes #1338	.udf disc images are unpacked with the bundled 7-Zip, like ISO and IMG. Read only, never a target.
[Format]: .rs .go .kt .swift .scala .scss .vue .tsx	no issue	Rust, Go, Kotlin, Swift, Scala, SCSS, Vue and TSX sources are read as plain text, the same way .java was added in #1176.

Features (label: enhancement)

Tag	Issue	What it does
[Feature]: Add iPhone ringtone (M4R) conversion	Fixes #1291	New .m4r audio output. It is always AAC in the iPod muxer, because iOS does not play ALAC ringtones.
[Feature]: Add Ukrainian (Українська) as a target language for the Translator (Ollama) engine	Fixes #1344	Українська is added to the Translate language list, with its code and English name for the prompt.

How it fits together

• .udf and .m4r are graded General, like ISO and M4B, so they appear with the other common formats.
• A settings migration (schema 77) teaches existing libraries the new extensions: text donut gets the 10 text extensions, archives donut gets .udf, audio donut gets .m4r. A donut that already claims one of them keeps it.
• Docs: docs/ENGINES.md lists the new formats.

Not included, on purpose

• .js, .php and shell scripts: they are programs and web pages, refused by WebFileNames.
• .djvu ([Format]: .djvu #1346): needs a separate engine, so it deserves its own PR.
• PDF to Excel ([Feature]: converter pdf to excel #1343): it already exists in the app.

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 every new text extension, UDF and M4R recognition, and the schema 76 to 77 migration (custom claims are kept, a second run changes nothing).
• tests/Filee.Core.Tests/FormatFieldsTests.cs: General grade count goes from 95 to 97.
• 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 AAC in the iPod muxer, even when ALAC is asked for.

Screenshots (UI changes)

None. The only visible 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)

This PR groups several small changes that share FormatRegistry.cs and the settings migration. I can split it by topic if you prefer.