Add incremental invalidation engine

Introduces a worklist-based invalidation engine that cascades changes
through the graph when documents are updated or deleted. Uses
ChildName/NestedName edges from the name_dependents index to propagate
invalidation with two distinct modes:

- Structural cascade (UnresolveName): declaration removed or scope broken
- Ancestor cascade (UnresolveReferences): ancestor chain changed

Replaces the has_unresolved_dependency runtime check with explicit
invalidation variants determined at queue time.

Author: st0012

rust/rubydex-sys/src/graph_api.rs

@@ -611,7 +611,7 @@ mod tests {
         indexer.index();
 
         let mut graph = Graph::new();
-        graph.update(indexer.local_graph());
+        graph.consume_document_changes(indexer.local_graph());
         let mut resolver = Resolver::new(&mut graph);
         resolver.resolve_all();
 

rust/rubydex/src/indexing.rs

@@ -95,7 +95,7 @@ impl Job for IndexingJob {
 /// Indexes a single source string in memory, dispatching to the appropriate indexer based on `language_id`.
 pub fn index_source(graph: &mut Graph, uri: &str, source: &str, language_id: &LanguageId) {
     let local_graph = build_local_graph(uri.to_string(), source, language_id);
-    graph.update(local_graph);
+    graph.consume_document_changes(local_graph);
 }
 
 /// Indexes the given paths, reading the content from disk and populating the given `Graph` instance.
@@ -123,7 +123,7 @@ pub fn index_files(graph: &mut Graph, paths: Vec<PathBuf>) -> Vec<Errors> {
 
     // Merge graphs as they arrive, overlapping with indexing work on other threads.
     while let Ok(local_graph) = local_graphs_rx.recv() {
-        graph.update(local_graph);
+        graph.consume_document_changes(local_graph);
     }
 
     for handle in handles {

rust/rubydex/src/model/declaration.rs

@@ -482,6 +482,10 @@ impl Namespace {
         all_namespaces!(self, it => it.member(str_id))
     }
 
+    pub fn remove_member(&mut self, str_id: &StringId) -> Option<DeclarationId> {
+        all_namespaces!(self, it => it.remove_member(str_id))
+    }
+
     #[must_use]
     pub fn singleton_class(&self) -> Option<&DeclarationId> {
         all_namespaces!(self, it => it.singleton_class_id())