Add Confirmer with cached confirmation state and predicate-based
parsing for yes/no and true/false inputs. Add ConfirmerSetup to
register the resource and auto-confirm when skip mode is enabled.
Add StandardInputArgsSetup to read piped stdin as appended arguments.
Reorganize module exports in res and setups.

Refactor program configuration types into a dedicated public `config`
module under `mingling_core`, making `StructuralRendererSetting`
accessible via `mingling_core::config` instead of the crate root.

Update all internal references and setup modules to use the new
`config::` path convention.

Mark all source files with a comment indicating they are not optimized
for documentation purposes.

Replace `ThisProgram` with `Self` where appropriate and
mark constructors as `#[must_use]` and `const` where possible.
Simplify explicit lifetimes in `ProgramSetup` and `Default`
implementations using elided lifetimes.