Rename declared entities to better reflect their semantics #948

Summary

Rename the declared_* source files and associated classes to names that more accurately communicate their semantics.

Motivation

The declared_* naming is not sufficiently descriptive of the role these entities play in the framework. Clearer terminology would make the implementation easier to understand and navigate.

Scope

• Review the semantics and responsibilities represented by the declared_* files and classes.
• Select consistent names that better express those semantics.
• Rename the files, classes, and references throughout the codebase.
• Update affected tests and verify the project builds and passes relevant tests.