* M3: team library analytics count detached instances
Detaching an instance of a library component counts it in the file (libraries.detached, saved with it, capped). The background library check reports the counts after its fetch (ReportDetached); the server keeps them per file beside the file's usage report in usage.json (same caps) and answers Detached with them. Show usage and library.usage list detaches per component and per file (detached, detachesKnown). The new request and reply variants are appended, so every older library message keeps its bytes; an older server refuses the new requests, which the app ignores. Gap 10.
* M3: the detach test waits for the instance count too (the two arrive in separate reports)