fix: retain semantic colors across editable diff updates

src/lsp.rs

@@ -238,8 +238,11 @@ impl Lsp {
             if !Arc::ptr_eq(&cached.snapshot, &snapshot) {
                 cached.snapshot = Arc::clone(&snapshot);
                 cached.diagnostics.clear();
-                cached.semantic_tokens = None;
-                self.changed_semantics.insert(snapshot.id);
+                if cached.semantic_tokens.take().is_some() {
+                    // Discard queued old coordinates, not explicit clears such as retirement.
+                    // The editor keeps remapped colors until a server reply replaces them.
+                    self.changed_semantics.remove(&snapshot.id);
+                }
                 self.changed_diagnostics.insert(snapshot.id);
             }
         }