Zoo 3.86.0 native container usage extraction

Official VSIX at fixed commit 6aa9d0174a9ecae155c6c5db9134bead4b67197d. Independent VS Code 1.140.0 called a local model through the public extension API. Preserve five messages’ type/say/ask, time, partial and verified usage fields; remove bodies, configuration and original task ID. api-usage.json is the independent service counter; extension-usage.json is the public usage callback.

One observed main request: input=6,118, output=53, derived total=6,171. Native cache/cost zeros are initialized defaults and stay unknown. Uncached/reasoning/source total/model/provider are unknown. Ordinary text/reasoning/resume prompts are not calls. The real task was publicly cancelled after receiving usage; no task-success claim. Historical migration tests use a separate synthetic usage-only extract to represent messages consumed by doc1, without claiming the old reader accepts this complete native array.