persist credits; new audio tags; sanitize tags; docker dev

[sevenrats]

Persist Credits

Before: Editions only stored author info. Non-author contributors like narrators and illustrators from the BookInfo API were discarded.

Now: Editions have a Credits list that captures non-author contributors (narrator, illustrator, editor, etc.) from the BookInfo API. These are stored as JSON in the database and exposed through the API.

Audio tag writing — narrator/illustrator

Before: Audio files had no narrator or illustrator tags.

Now: Narrator and illustrator are read from edition credits and written to all 5 tag formats (ID3v2 TXXX frames, Xiph fields, APE items, ASF descriptors, Apple dash boxes). The Diff method also tracks changes to these fields.

Audio tag writing — cover art atom ordering fix

Before: Cover art was written in the middle of tag assignment, before format-specific tags. In M4B files this put the large covr atom before aART, trkn, ©day, and all ---- dash boxes. Some parsers (ATL) stop reading ilst children after a large covr atom and miss everything after it.

Now: Cover art is written last, after all format-specific tags. The covr atom lands at the end of the ilst container so all metadata atoms precede it.

Audio tag writing — null byte sanitization

Before: String values from the database were written to tags as-is. If a field contained null bytes or other control characters (e.g. Dungeon Crawler Carl's description), they were embedded into the file, corrupting the tag.

Now: All string fields are stripped of null bytes and C0 control characters (except tab/newline/CR) before writing. Empty results become null so nothing is written.

Docker dev build

Before: No way to build a Docker image without host tools. The existing Dockerfile expected pre-built artifacts.

Now: docker/Dockerfile.dev is a multi-stage build (dotnet SDK → node → alpine runtime) that compiles everything inside Docker. Copies .editorconfig and Logo/ which are required for the build but live outside src/.

[sevenrats]

closing in favor of upstream
mono/taglib-sharp#377