Sage scoping finding (owner directive: Glove must stay general): the
reusable seam was named after a single harness. Rename the virtual
channel interface to wallet_status_projection_channel and the options
struct to wallet_status_projection_options; any guest harness may now
implement the seam. The concrete wallet_pi_status_adapter keeps its
Pi name with the explicit "Pi-shaped projection only" caveat, keeping
the general mechanism honest about which projections are Pi-specific.
No behavior change; mechanical rename. Validation (umask 0022):
dev CTest 79/79, ASan/UBSan 79/79, TSan 79/79; clang-format clean;
git diff --check clean.