Move components into crates, enforce deterministic component availability

[ERnsTL]

Task 7 — Enforce Deterministic Component Availability

Objective

Ensure components must exist as Cargo dependencies.

Requirements

1. Components must be declared in Cargo.toml:

repeat_component = { path = "components/repeat_component" }

2. Build must fail if:

   • A configured crate cannot be resolved.
   • A struct name does not exist.

No dynamic loading. No modules, but components must be present in crates.

Add version compatibility check, see component crate version schema in README.