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>

tests/editor/annotation-drag.test.ts

@@ -0,0 +1,88 @@
+/**
+ * A drag in the graph moves everything it carries exactly once. A group carries the nodes centred
+ * in it and the boxes inside it; a band may have caught a group *and* one of its nodes – that node
+ * is claimed twice and must move once, or it would end up twice as far as the rest.
+ */
+import { describe, expect, it } from 'vitest';
+import type { Graph, GraphNode } from '../../src/core/graph';
+import {
+  annotationBoxes,
+  boxSeeds,
+  placeTravellers,
+  recordTravellers,
+  travellers,
+} from '../../src/editor/graph/annotationDrag';
+import type { Box } from '../../src/editor/framing';
+import { makeBehavior, makeProject } from '../helpers';
+
+const node = (id: string, x: number, y: number): GraphNode => ({ id, type: 'Add', x, y, params: {} });
+const NODE = { w: 100, h: 50 };
+const drawn = (graph: Graph): Box[] => graph.nodes.map((n) => ({ id: n.id, x: n.x, y: n.y, ...NODE }));
+
+/** An outer group holding an inner group and a comment; `in` sits in both groups, `far` in neither. */
+function graph(): Graph {
+  return {
+    nodes: [node('in', 120, 120), node('edge', 20, 20), node('far', 900, 900)],
+    edges: [],
+    groups: [
+      { id: 'outer', x: 0, y: 0, w: 400, h: 300, text: 'Outer' },
+      { id: 'inner', x: 100, y: 100, w: 150, h: 100, text: 'Inner' },
+    ],
+    notes: [{ id: 'note', x: 300, y: 200, w: 80, h: 60, text: 'Careful' }],
+  };
+}
+
+describe('what a group drag carries', () => {
+  it('takes the nodes centred in it, the boxes inside it, and their nodes – each once', () => {
+    const g = graph();
+    const along = travellers(g, drawn(g), boxSeeds(g, ['outer']), []);
+    expect(along.boxes.map((b) => b.id).sort()).toEqual(['inner', 'note', 'outer']);
+    // `edge` is centred at (70, 45), inside; `in` is inside both groups but listed once; `far` is not.
+    expect(along.nodes.map((n) => n.nodeId).sort()).toEqual(['edge', 'in']);
+  });
+
+  it('claims a node once even when the band caught both it and its group', () => {
+    const g = graph();
+    const along = travellers(g, drawn(g), boxSeeds(g, ['outer']), ['in', 'far']);
+    expect(along.nodes.map((n) => n.nodeId).sort()).toEqual(['edge', 'far', 'in']);
+    placeTravellers(g, along, () => ({ x: 10, y: 0 }));
+    expect(g.nodes.map((n) => n.x)).toEqual([130, 30, 910]);
+    expect(g.groups?.map((b) => b.x)).toEqual([10, 110]);
+    expect(g.notes?.map((b) => b.x)).toEqual([310]);
+  });
+
+  it('carries nothing along for a comment, which frames nothing', () => {
+    const g = graph();
+    const along = travellers(g, drawn(g), boxSeeds(g, ['note']), []);
+    expect(along.boxes.map((b) => b.id)).toEqual(['note']);
+    expect(along.nodes).toEqual([]);
+  });
+
+  it('leaves out the grabbed box when asked, so it is not seeded twice', () => {
+    const g = graph();
+    expect(boxSeeds(g, ['outer', 'note'], 'outer').map((b) => b.id)).toEqual(['note']);
+    expect(annotationBoxes(g).map((b) => b.id)).toEqual(['outer', 'inner', 'note']);
+  });
+});
+
+describe('writing a drag back', () => {
+  it('records one command per traveller from the start to where the preview left it', () => {
+    const f = makeProject();
+    const behavior = makeBehavior(f, 'B');
+    const g = behavior.graph;
+    g.nodes.push(node('a', 0, 0));
+    g.groups = [{ id: 'grp', x: -50, y: -50, w: 200, h: 200, text: 'G' }];
+    const along = travellers(g, drawn(g), boxSeeds(g, ['grp']), []);
+    placeTravellers(g, along, () => ({ x: 24, y: 48 }));
+
+    const commands = recordTravellers(g, behavior.id, along);
+    // The preview is undone in the model, so the commands own the whole change…
+    expect(g.nodes[0]).toMatchObject({ x: 0, y: 0 });
+    expect(g.groups[0]).toMatchObject({ x: -50, y: -50 });
+    // …and running them lands everything where the drag ended.
+    for (const command of commands) command.execute(f.project);
+    expect(g.nodes[0]).toMatchObject({ x: 24, y: 48 });
+    expect(g.groups[0]).toMatchObject({ x: -26, y: -2, w: 200, h: 200 });
+    expect(commands).toHaveLength(2);
+  });
+});