Enforce public API documentation with #![warn(missing_docs)]

[jose-compu]

Description

The library exposes many public types and functions but does not enforce documentation. Adding #![warn(missing_docs)] ensures all public API items have doc comments, which also improves the docs.rs output.

Proposed Changes

• Add #![warn(missing_docs)] to lib.rs
• Add doc comments to all public types, traits, functions, and methods
• Add module-level documentation for each module
• Add crate-level documentation with usage examples in lib.rs

Impact

Better docs.rs output and a more professional public API surface.