Adapt to two contract changes master introduced:
- The generated Remote face now wraps every business result in
RemoteResult, folding carrier failures into an ok:false branch instead
of rejecting. The controller reads that envelope at its three call
sites and maps a carrier failure onto the same settled shape the
controls already render; three specs cover the new branch.
- Client packages split their tsconfig into host and client halves, and
the host aggregate now compiles any test not named *.client.spec.*.
Rename this package's specs to the client convention and drop the
../connection project reference, which pointed at a solution file that
no longer carries the client sources.
Keep master's mount loop with its rollback-on-failure in api-remotes and
add messageFeedbackRemote to it.
SessionPersistence.readRaw previously used undefined for two unrelated states: a supported backend could not find the requested session, or the backend had no per-session artifact concept at all. The export endpoint consequently reported an existing SQLite-backed session as HTTP 404, which falsely diagnosed storage capability as session absence.
Make raw-artifact support an explicit backend capability. Unsupported backends now fail their inherited readRaw path loudly and the host answers 501 before reading, while undefined retains the single meaning of an absent artifact on a supporting backend. First-party backends, test providers, generated API catalogs, bilingual persistence docs, and export error contracts now state that distinction; focused tests cover both the 501 and the inherited rejection.