QDoc currently has inconsistent and scattered logic for determining which nodes
should be included in documentation generation. Different components use ad-hoc
checks that combine direct `isInternal()` calls with `Config::showInternal()`
queries, separate private member inclusion flags (`includePrivate*`),
generator-specific caching of configuration state, and duplicated filtering
logic across HTML, DocBook, and WebXML generators.

This results in needless code duplication across generators and filters. It may
also possibly be the source of inconsistent behavior between output formats,
certainly as the generators diverge in features. Extending inclusion rules
becomes difficult, and testability of inclusion logic is practically
non-existent. It also causes tight coupling between generators and
configuration.

Recently, a series of changes introduced the inclusion strategy pattern to the
QDoc codebase. It's meant to:

1. Centralize inclusion policy in `InclusionPolicy` struct containing all relevant flags
2. Standardize node context in `NodeContext` struct capturing node characteristics
3. Provide unified filtering through `InclusionFilter` with intention-revealing methods
4. Use efficient flag-based matching with `InclusionFlags` enum for performance
5. Eliminate scattered checks by migrating all components to use the centralized system

This task serves as documentation for the effort to transition QDoc towards
making full use of the inclusion strategy pattern.