khive-fold: Cognitive primitives — Fold, Anchor, Objective, Selector.

Four cognitive primitives that form the "paper-folding" operation:

• Fold: entries → derived state (deterministic reduce)
• Anchor: causal graph traversal (provenance chains)
• Objective: score candidates and select best
• Selector: budget-constrained pack (many → subset)

Plus deterministic ordering primitives, composition combinators, and common strategies (Recency, Relevance, Weighted, etc.).

Quick Start

use khive_fold::{fold_fn, Fold, FoldContext};

let counter = fold_fn(
    |_ctx| 0usize,
    |count, _entry: &i32, _ctx| count + 1,
);

let entries = [1, 2, 3, 4, 5];
let result = counter.derive(entries.iter(), &FoldContext::new());
assert_eq!(result.state, 5);