1.1.5

docs(phpdoc): deepen breadcrumbs package docs

The breadcrumbs package had functional PHPDoc, but many core types,
contracts, and exceptions still read thinner than the established Cline
package standard in warden and toggl.

This updates the package comments to explain lifecycle position,
resolution order, invariants, side effects, and failure behavior so
maintainers can understand the design without tracing every caller.

Side effects: PHPDoc alignment in DefinitionDiscovery now matches ECS
formatting expectations, but runtime behavior is unchanged.