v2.35.2 — verification stats + validator consolidation

Verification observability and a validator consolidation.

• Added resolve_control(action="verification_stats") returns a process-level tally of readback-verification outcomes (verified / contradicted / unverified) since server start. A rising contradicted count means the Resolve API reported success but a readback disagreed. No connection required.
• Changed open_page validates its page argument through the declarative contract layer instead of a hand-written enum check — behavior unchanged; part of folding scattered validation into one place.