getServerBoundPlexClient/getClientForLibrary existed only for their own unit tests; MetadataEditAdapter.backend and Plex's unreachable prefKey fallback and music-kind branches had no production path (edit is double-gated on supportsKind); MainScreenFocusScope's focus aspect, isSidebarFocused, and focusContent were write-only; resolveActivePlexIdentity.preferredAccount was never passed; ProfileRegistry.get was unused outside tests — its removal exposed a stale test contract, now pinned correctly: list() deliberately never serves plex_home rows.
Introduces shared seams for paginated views, D-pad reorder, media control
routing, async singletons and the device method channel, then points the
open-coded copies at them.
Also removes unused models and duplicated provider/server plumbing, folds
the twice-implemented artifact store in the server, and factors the
repeated Flutter toolchain prologue in CI into a composite action.
edde746