Verify import-infobox completions on-wiki (5th verification task) + ledger-source impact tiles 6/7

Counting the import ATTEMPT click as completion overcounted (failed imports counted); switching to the success cta would have erased all real history (outcome ctas exist only since 2026-07-21). Instead: the kit's own edit-summary token attests every import on-wiki. Registers import-infobox in VERIFIABLE_TASKS (dashboards flip to the ledger), credits in-flow from the import route + a summary-token contribs sweep (recovers the whole pre-cta era), extends verify-completions.js as the backfill, fixes the session-level cta signal, and re-sources impact tiles 6/7 from the ledger. Deploy coupling: registration + backfill in one window — see deploy-runbook-import-infobox.md.