Remove the generic parameter `C` from `DirectoryEnvironmentSetup`,
making it a unit struct that no longer requires `::<C>::default()` for
construction. Update the `ProgramSetup` impl and the `setup` method
signature accordingly, and improve the doc comments.

Rename `Confirmer` resource to `ResConfirm`, `ConfirmerCount` to
`ConfirmCount`, and `ConfirmerPredicate` to `ConfirmPredicate`. Update
related setups, guards, and documentation references.

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.