Added dev test tools and CLAUDE.md

dev/: test asset files, a fake Libreflow IPC server and an end-to-end
Scene Manager test (excluded from the extension build). CLAUDE.md: notes
for working on the add-on (conventions, testing, design findings, open
points).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dev/make_test_assets.py

@@ -0,0 +1,53 @@
+"""Write the asset files used by fake_libreflow.py into <workdir>/lib.
+
+    blender -b --factory-startup --python dev/make_test_assets.py -- <workdir>
+
+bob: a rig (COL_bob: armature + meshes), v001 has 1 mesh, v002 has 2.
+tree: COL_tree, plus an unrelated top-level collection.
+rock: a single top-level collection not named after the asset (fallback case).
+"""
+
+import os
+import sys
+
+import bpy
+
+WORKDIR = sys.argv[sys.argv.index("--") + 1]
+
+
+def mesh_object(name):
+    mesh = bpy.data.meshes.new(name)
+    mesh.from_pydata([(0, 0, 0), (1, 0, 0), (0, 1, 0)], [], [(0, 1, 2)])
+    return bpy.data.objects.new(name, mesh)
+
+
+def write(path, collection_name, meshes=1, rig=False, extra=False):
+    bpy.ops.wm.read_homefile(use_empty=True)
+    scene = bpy.context.scene
+    collection = bpy.data.collections.new(collection_name)
+    scene.collection.children.link(collection)
+    parent = None
+    if rig:
+        parent = bpy.data.objects.new("RIG_" + collection_name, bpy.data.armatures.new("RIG_" + collection_name))
+        collection.objects.link(parent)
+        bpy.context.view_layer.objects.active = parent
+        bpy.ops.object.mode_set(mode="EDIT")
+        bone = parent.data.edit_bones.new("root")
+        bone.tail = (0, 0, 1)
+        bpy.ops.object.mode_set(mode="OBJECT")
+    for index in range(meshes):
+        ob = mesh_object(f"GEO_{collection_name}_{index}")
+        ob.parent = parent
+        collection.objects.link(ob)
+    if extra:
+        scene.collection.children.link(bpy.data.collections.new("WIP_other"))
+    os.makedirs(os.path.dirname(path), exist_ok=True)
+    bpy.ops.wm.save_as_mainfile(filepath=path)
+
+
+lib = os.path.join(WORKDIR, "lib")
+write(os.path.join(lib, "bob", "v001", "rig.blend"), "COL_bob", meshes=1, rig=True, extra=True)
+write(os.path.join(lib, "bob", "v002", "rig.blend"), "COL_bob", meshes=2, rig=True, extra=True)
+write(os.path.join(lib, "tree", "v001", "model.blend"), "COL_tree", extra=True)
+write(os.path.join(lib, "rock", "v001", "rock.blend"), "rock_geo")
+print("Test assets written in", lib)