Crate README inventory

Crate and package README files remain canonical at their package paths because crates.io, IDEs, and repository browsers expect them there. The docs site links them and hosts cross-cutting guides separately.

README	Purpose
crates/ferrex-contracts/README.md	Trait surfaces and domain contracts built atop ferrex-model.
crates/ferrex-model/README.md	Shared media, library, user/auth, and metadata models.
crates/ferrexctl/README.md	Configuration bootstrapper and packaging CLI usage.
crates/ferrex-player/README.md	Desktop player facade, runtime notes, screenshots, validation, HDR, and Flatpak notes.
crates/ferrex-player-foundation/README.md	Dependency-light player primitives and boundary policy link.
crates/ferrex-player-repository/README.md	Player-side media repository overlays and server-scoped disk cache support.
crates/ferrex-player-ui/README.md	Desktop presentation layer during player crate decomposition.
crates/ferrex-core/tests/README.md	Core test suite and scanner runtime regression commands.
crates/ferrex-server/tests/README.md	Server E2E and scanner regression-suite commands.

For cross-crate architecture, use Architecture. For player dependency direction and guard policy, use Player dependency boundaries.