WIP: capture sharpening

Checkpoint committed by the coordinator, not by the authoring agent: the
session hit its API limit mid-task and left this work uncommitted. Committed
so it survives, NOT because it is finished - expect failing tests and
half-applied changes. The agent resumes from here.

core/dr-pipeline/src/ops/mod.rs

@@ -22,10 +22,20 @@
 //! reason rather than for want of migrating. The tone curve interpolates
 //! between five points and its neutral is a *relationship* between them; the
 //! colour mixer generates thirty-six faceted parameters from twelve computed
-//! hue bands; [`vignetting`] carries lens-profile coefficients that are not
+//! hue bands; [`capture_sharpen`] is a convolution, and the schema describes a
+//! fragment handed a colour with no way back to a coordinate;
+//! [`vignetting`] carries lens-profile coefficients that are not
 //! parameters at all. A schema stretched to cover those would be a worse
 //! language than Rust, aimed at one caller each.
 //!
+//! # The neighbourhood nodes
+//!
+//! [`capture_sharpen`] reads the pixels around the one it writes, so it runs
+//! in [`crate::detail`]'s stage after the fused pass rather than as a fragment
+//! within it. It is an ordinary [`Operation`](crate::Operation) in every other
+//! respect — descriptor, parameters, sidecar, history — which is what lets the
+//! panel, the presets and the undo stack carry it with no special case.
+//!
 //! Both publish the same [`crate::descriptor::OpDescriptor`], so nothing
 //! downstream can tell them apart. A hand-written node still declares its
 //! place in the chain in `ops/<id>.yaml` with `rust:`, so the directory
@@ -41,12 +51,14 @@
 // Hand-written nodes. Each is listed in `ops/` with `rust:`, which is what
 // places it in the chain; these are the implementations that entry points at.
 pub mod aberration;
+pub mod capture_sharpen;
 pub mod colour_mixer;
 pub mod curve;
 pub mod distortion;
 pub mod vignetting;
 
 pub use aberration::Aberration;
+pub use capture_sharpen::CaptureSharpen;
 pub use colour_mixer::ColourMixer;
 pub use curve::ToneCurve;
 pub use distortion::Distortion;