Add node macro support for injecting nodes into global scope (#4221)

* Macro support

* Preprocessor support

* Allow Cow str as scope name

* Use Passthrough node to work around compiler auto wrapping the producer node and invalidating the node id

* Stable NodeIds

* Less hacky but with bad performace

* Remove Cow from RegistryValueSource::Scope

* Connect scope injections to the inner network export

---------

Co-authored-by: Dennis Kobert <dennis@kobert.dev>

node-graph/libraries/core-types/src/registry.rs

@@ -17,6 +17,7 @@ pub struct NodeMetadata {
 	pub properties: Option<&'static str>,
 	pub context_features: Vec<ContextFeature>,
 	pub memoize: bool,
+	pub inject_scope: bool,
 }
 
 // Translation struct between macro and definition

node-graph/libraries/core-types/src/types.rs

@@ -154,6 +154,13 @@ impl ProtoNodeIdentifier {
 	pub fn as_str(&self) -> &str {
 		self.name.as_ref()
 	}
+
+	pub const fn as_static_str(&self) -> &'static str {
+		match self.name {
+			Cow::Borrowed(name) => name,
+			Cow::Owned(_) => panic!("`as_static_str` called on a `ProtoNodeIdentifier` backed by an owned string"),
+		}
+	}
 }
 
 impl Display for ProtoNodeIdentifier {