Extracts two self-contained, framework-agnostic modules out of
src-tauri so they can be reused by other clients without duplicating
logic:
- ImageCacheService / ImageCacheStats move into the qbz-cache crate
(LRU disk cache, MD5-keyed, SQLite index).
- The credential store (keyring + AES-256-GCM encrypted file for Qobuz
credentials and the OAuth token) moves into a new qbz-credentials
crate.
src-tauri/image_cache.rs and src-tauri/credentials/mod.rs become thin
re-exports, keeping their Tauri managed-state wrappers. The Tauri app
is behavior-identical; both modules were already self-contained (no
Tauri and no crate:: references).
cc
vicrodh
3477edfb76