[cpp-RCP-07] CLI capabilities self-report advertises "loaning" without exporting a LoaningController #75

Location: include/rcp/cli.hpp — capabilities_json() (~lines 96-113).

Finding: The CLI's capabilities self-report JSON lists "loaning" in its features array, while optional_interfaces is empty and no LoaningController is actually wired into the CLI-exposed surface — the header's own comment notes that Adapt() stopped wrapping LoaningController at the milestone that reshaped it to a plain callable. So the self-report currently claims a capability the CLI doesn't actually expose. This matters specifically because the RELAY conformance gate exercised in CI is meant to check self-reported capabilities against what's actually wired up, and a capability claim that doesn't match reality defeats that check.

Recommendation: Only include "loaning" in the reported feature set when a LoaningController (or equivalent) is actually reachable through the CLI/Adapt path; otherwise drop it from capabilities_json().

Verification: Independently re-read include/rcp/cli.hpp against current HEAD (commit 4b9449a, 2026-07-29). Confirmed "loaning" appears in the features list, optional_interfaces is [], and the header's own comment states Adapt() no longer wraps LoaningController.

Filed from the 2026-07-29 ecosystem audit register; independently re-verified against current HEAD before filing.