fix: validate consistency findings and retain partial review coverage

[ZeroPoint95]

• Reject negative consistency claims without an explanation and valid source location before report assembly and posting; retain non-postable failure records.
• Persist partial-review coverage facts and warnings, preserving successful execution status for assembled partial reports. Partial posting payloads retain findings while removing clean merge recommendations and approvals.
• Refuse older reports with known partial metadata that lack durable coverage warnings; preserve compatibility for older reports without known partial facts. Document the behavior.

Validation: failing-before/passing-after offline assembly and posting regressions, review-package and race suites, required build and exact-base PR gate, independent review.

Live release acceptance remains incomplete: the retained trial was partial, with three lens session deadlines and malformed model content. No new live trial was run for this repair; models and cost/time/turn limits are unchanged.