Research: functional and specification-style pattern candidates

[Skymly]

Part of #244

Question

For the functional / specification-style family, which new pattern domain candidates fit DesignPatterns’ primitive + compile-time-glue model (e.g. Specification and nearby forms)?

Constraints: longlist only; new domains only; no admission ranking.

Output: 2–4 candidates (name + one-line shape). Research note on research/ branch; link from this issue.

[Skymly]

Research note (longlist only; no admission ranking):

https://github.com/Skymly/DesignPatterns/blob/research/functional-spec-candidates/docs/.Local/research/functional-spec-candidates.md

Branch: research/functional-spec-candidates

Candidates:

• Specification — ISpecification<T> + And/Or/Not; attribute registration → Keys / composition / DI (Evans–Fowler selection, validation, construction-to-order uses).
• Interpreter (expression / rule trees) — leaf + composite nodes with compile-time operator/node registration (Composite Spec strategy in Evans–Fowler uses GoF Interpreter).
• Query Object (criteria-as-object) — first-class selection criteria (often Expression-/repository-facing), distinct from in-memory IsSatisfiedBy.
• Production Ruleset (condition → action) — ordered/priority rules pairing a Spec-like condition with an effect; generator wires order / Keys / diagnostics.

Note: F3 pool Builder is creational (GoF), not listed here; Fowler construction-to-order is a Specification use, not Builder.

Map #244 left untouched.