Add high-level helpers for consuming complete paginated library results

[zeevenn]

What to build

Add a higher-level JS-facing helper or documented pattern for consuming complete paginated Local Music Library results so app code does not repeat Cursor pagination loops for Tracks, Albums, and Artists.

The low-level paginated Interface should remain available. This issue adds leverage above it for common app workflows that need the full current Track, Album, or Artist list.

Acceptance criteria

• App code can fetch all Tracks, Albums, or Artists without repeating a manual while hasNextPage loop at each call site.
• The helper preserves existing low-level paginated methods for callers that need manual pagination.
• Cursor handling, page size defaults, and termination behavior are centralized in the JS implementation.
• Example app screens use the shared helper or shared pattern instead of duplicating pagination loops.
• Tests cover normal pagination, empty results, missing endCursor, and defensive loop termination behavior.

Blocked by

• Deepen Track sort and pagination contract #13