Hand out descriptors a declaration could produce

`Operation::descriptor()` returned `&'static OpDescriptor`, and that lifetime
is the whole reason a build-time node is free and a run-time node is
impossible: only a compile-time literal can satisfy it, so no amount of
reading `ops/*.yaml` at startup could ever produce a descriptor the rest of
the application would accept. FR-PLG-2 says a bundled operation and a
third-party plugin are the same kind of thing, differing only in where the
file was found — and a lifetime outsiders cannot meet is exactly the second,
weaker format that requirement forbids.

So a descriptor is now owned and handed out as `Arc<OpDescriptor>`, with `Vec`
where it held `&'static` slices. `Arc` rather than a `&self`-borrowed
reference because the callers want to *keep* it: the develop panel collects
descriptors and then mutates the graph, and a borrow would tie the
descriptor's lifetime to a borrow of the operation it came from, which is the
one thing `&'static` was doing right.

The identifier newtypes deliberately did not follow. `ParamId` is `Copy`, is
compared in `match` arms against generated constants, is a map key in the
sidecar and history, and reaches Slint model rows; an `Arc<str>` there would
cost a refcount on every one of those and would take `match id { EXPOSURE =>
.. }` away from the generated code. They gain an interner instead, which is
honest about its lifetime rather than pretending to one — the set of ids is
bounded by deduplication and is process-lifetime by construction, because the
sidecar on disk names its parameters and an id has to stay resolvable for as
long as any edit naming it can be opened.

No behaviour changes. Every descriptor that was a `static` is a `LazyLock`
initialiser now, `Operation::helpers` borrows from `self` instead of being
`'static` so a future run-time node can own its list, and `Warp` and `Framing`
follow `Operation` so there is one shape rather than two.

The one place a descriptor is read per frame is `compose_full`, which takes
`descriptor().id` to prefix each active operation's uniforms, and `dr-ui`
composes on every frame it draws. That is a dozen atomic increments beside a
composition that is already building several kilobytes of WGSL on the same
call; it is noted at the trait method rather than left for a profiler to find.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

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

@@ -153,6 +153,7 @@
 //! this file.
 
 use std::marker::PhantomData;
+use std::sync::{Arc, LazyLock};
 
 use crate::descriptor::{Attribute, LocalizedKey, OpDescriptor, OpId, ParamDescriptor, ParamId};
 use crate::detail::{DetailPass, DetailStage, RenderScale};
@@ -181,7 +182,12 @@ const TRUNCATION: f32 = 2.0;
 /// between clarity and texture can be read side by side, which is the one
 /// thing a reader comes to this file to do.
 pub struct Recipe {
-    descriptor: &'static OpDescriptor,
+    /// The static this operation's descriptor is built in. A `LazyLock`
+    /// rather than a reference to a descriptor, because a descriptor is an
+    /// owned value handed out as an `Arc` now (FR-PLG-2), and a `const`
+    /// recipe cannot hold an `Arc` — only a reference to the static that
+    /// makes one.
+    descriptor: &'static LazyLock<Arc<OpDescriptor>>,
     helpers: &'static [Helper],
     /// The Gaussian's σ, as a fraction of the frame's shorter edge.
     sigma: f32,
@@ -253,19 +259,23 @@ impl Band for Fine {
     };
 }
 
-static CLARITY_DESCRIPTOR: OpDescriptor = OpDescriptor {
-    id: CLARITY,
-    label: LocalizedKey("op.clarity"),
-    params: &[ParamDescriptor::amount("amount", "param.clarity.amount")],
-    attributes: &[Attribute::Detail],
-};
+static CLARITY_DESCRIPTOR: LazyLock<Arc<OpDescriptor>> = LazyLock::new(|| {
+    Arc::new(OpDescriptor {
+        id: CLARITY,
+        label: LocalizedKey("op.clarity"),
+        params: vec![ParamDescriptor::amount("amount", "param.clarity.amount")],
+        attributes: vec![Attribute::Detail],
+    })
+});
 
-static TEXTURE_DESCRIPTOR: OpDescriptor = OpDescriptor {
-    id: TEXTURE,
-    label: LocalizedKey("op.texture"),
-    params: &[ParamDescriptor::amount("amount", "param.texture.amount")],
-    attributes: &[Attribute::Detail],
-};
+static TEXTURE_DESCRIPTOR: LazyLock<Arc<OpDescriptor>> = LazyLock::new(|| {
+    Arc::new(OpDescriptor {
+        id: TEXTURE,
+        label: LocalizedKey("op.texture"),
+        params: vec![ParamDescriptor::amount("amount", "param.texture.amount")],
+        attributes: vec![Attribute::Detail],
+    })
+});
 
 /// Luminance as a position on a logarithmic scale, floored.
 ///
@@ -394,8 +404,8 @@ impl<B: Band> LocalContrast<B> {
 }
 
 impl<B: Band> Operation for LocalContrast<B> {
-    fn descriptor(&self) -> &'static OpDescriptor {
-        B::RECIPE.descriptor
+    fn descriptor(&self) -> Arc<OpDescriptor> {
+        Arc::clone(B::RECIPE.descriptor)
     }
 
     fn set_param(&mut self, _id: ParamId, value: f32) {