Three stores, three importers and three pickers that differ only in their type are one of each (#85)

Refactoring round one: HttpFontStore/HttpSoundStore/HttpTextureStore collapse into a generic
HttpFileStore over a FileStore contract; fontImport/soundImport/textureImport share assetImport
with an ImportKind per sort; ImagePicker/FontPicker/SoundPicker sit on FilePicker and describe
only their row. The group/comment drag logic leaves GraphCanvas for annotationDrag.ts (with its
own unit test), declaredRows.ts replaces the duplicated row build in particles.ts and shaders.ts,
and dead code in font/sound/compile/emission/transform/actions is gone. README: asset list,
check count 958, the two-job CI, the Scenes wiki page.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/editor/actions.ts

@@ -58,16 +58,6 @@ export function removeNodes(state: EditorState, assetId: string, nodeIds: readon
   return commands.length > 0 && state.execute(oneStep(`Delete ${commands.length} nodes`, commands));
 }
 
-/**
- * Deletes a group or comment and leaves every node alone – which is the point, so the caller does
- * not have to know which of the two lists holds it either.
- */
-export function removeAnnotation(state: EditorState, assetId: string, annotationId: string): boolean {
-  const graph = findGraphAsset(state.project, assetId)?.graph;
-  const found = graph && findAnnotation(graph, annotationId);
-  return Boolean(found) && state.execute(new RemoveAnnotationCommand(assetId, found!.kind, annotationId));
-}
-
 /**
  * Deletes everything a graph selection holds – nodes and boxes alike – as one undo step, since one
  * band caught them and one keypress asked for them to go. Boxes still take none of their nodes.