Continue Blender Web parity task handoff

docs/status/M16-GAP-00223.md

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+# M16-GAP-00223 Status
+
+status: done
+task: armature.collection_create_and_assign operator LOCAL_EXACT slice
+updated: 2026-08-22 America/New_York
+
+scope:
+
+- The minimal fixture contains one armature bone assigned to `WebGapArmatureCollectionCreateAssignSource`.
+- Desktop runs `ARMATURE_OT_collection_create_and_assign(name=WebGapArmatureCollectionCreateAssignNew)` with `poll=true` and `FINISHED`, creating and activating the new collection while assigning the selected bone and preserving source membership through save/reopen.
+- The existing Main reader exposes both collection member ID lists and collection indices; no new reader field, data-block, editor, or browser behavior was added.
+
+evidence:
+
+- The generator, desktop checker, npm comparator, direct comparator, and task-context checks passed. Repeated checker runs recognize the persisted created collection and remain idempotent.
+- WASM/Main observes the same created collection, active ordering, and assigned bone ID, preserves them across save/reopen, and rejects malformed Blend input without Main mutation.
+- Chromium-only policy was preserved; no Firefox/WebKit run was made.
+
+nextTask: `M16-GAP-00224`