Review asked whether composing a preset per session compounds memory.
Measured against the shipped compositions: it does not compound — growth
is strictly linear at ~0.17 MB per agent on `minimal` and ~1.31 MB on
`standard`, the first agent of a process pays ~7 MB more for module
imports every later mount shares, and disposal returns essentially all
of it.
What the measurement did find is that nothing disposes. The api-proxy
discards the handle it creates, archiving only edits the workspace
registry, the registry has no eviction, and the sole disposal site in
the host is the JSON-RPC server's shutdown. A preset did not introduce
that; it raised the per-session price from ~0.2 MB to ~1.3 MB and made
it visible.
Recorded as a remaining TODO rather than fixed here: eviction belongs to
the host that owns the handle, not to this seam.