Check saved ads against the enabled rules and record cases

Evaluates every enabled policy rule of the project against the saved checks in a date range (last 30 days by default, at most 92 days), like "Evaluate saved ads" in the app. New matches are recorded as findings and open or update cases; a resolved case reopens only for an ad observed after it was resolved. Review matches with list_policy_cases and list_policy_case_evidence before deciding what they mean. Repeating the call records nothing twice. New captures are evaluated automatically; use this after adding or changing a rule to review older checks. A match is a lead to review: an observation shows an ad was displayed for a search at a moment, not proof of a violation, spend or a purchased keyword. Requires the write scope.