Consuming apps depend on this crate from a local checkout, and the
operations were hard to find: the crate root was `pub use waku_sys::*`,
so everything a caller can do was hidden as methods on a glob-exported
LogosDeliveryCtx.
The crate-root docs now carry an Operations map — node lifecycle,
messaging, reliable channels, and the typed event listeners — with the
method names and a runnable example, so `cargo doc` and reading lib.rs
both show what is callable. The low-level waku_* kernel surface is noted
as the tier beneath.
The README gains a "Using the crate" section: clone + checkout, the
local path dependency, and the Nim/make/Rust build prerequisites.
Also fixes stale rustdoc links in the restored store DTOs and a bare URL
in the config docs, so the doc build is warning-clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>