Promote the runtime per-instrument flag from a bare reason
string to an InstrumentStatus enum so later kinds (load,
reload, compile failures) can share the surface. Behaviour
is unchanged: skipIfIncompatible sets .incompatible and the
sidebar still renders a single warning icon.
Each instrument carries an InstrumentCompatibility (platforms,
osIDs, archs; nil set means any). Hook pack manifests and custom
defs declare it; tracer and codeshare default to universal.
System parameters are queried lazily via SystemParametersCache,
keyed by device id and invalidated when devices disappear.
Restoring an incompatible instrument now marks it with a reason
on its InstrumentRef instead of attaching.
Ole André Vadla Ravnås