Replace the Go backend with the Rust workspace and route Android/iOS through
UniFFI bindings. Include the migrated extension runtime, network, providers,
media metadata, downloads and library operations, with version 5.0.0+147.
Remove Go sources, adapters, native build selection and CI dependencies.
Build Rust unconditionally and lock the iOS Rust pod using a relative path.
Retain legacy source and migration evidence in a local ignored archive.
Validation: Android Kotlin compile and 53 native tests; Swift Rust-branch
equivalence and syntax; CocoaPods install; workflow, shell, Ruby, plist and
diff checks. Reuse the preceding 100 Rust tests, fmt/Clippy and five-ABI
build checkpoint; no new APK or iOS application build for this cleanup.
Known follow-up: URL/URLSearchParams globals are missing from the Rust JS
runtime. A controlled extension replay confirms a URL-resolution regression;
this commit does not fix that runtime gap.
Preserve audio and artwork while replacing conflicting Opus gain tags with R128 comments. Verify manual, download, and album writes, handle SAF failures, and refresh playback normalization after saving.
Apply resolved metadata with copyWith and retain the existing field precedence. Keep UPC, preview URLs, and source-only fields when enrichment updates other tags.
Extract the pure merge helpers and add regression tests for field preservation.
Both call sites used a bare dart:io HttpClient with no timeout, retry, or
cache; downloadCoverToFile provides all three (plus the singleflight cover
cache) and can hang-proof the embed path.
Pure move: paths, native worker, finalization, ReplayGain, and
metadata embedding move to part files as private extensions on
DownloadQueueNotifier; queue orchestration, state, and public API
stay in the main file (7598 -> 4022 lines).
zarzet