RAG 0.19.0: research evidence and review quality

Research now preserves space for follow-up evidence, copies model-selected source passages into citations, checks relevance/entity/time/scope, and continues from retrieved evidence after an invalid planner response. Hosts can configure a separate review provider/model through the existing accounting path.

Validation: 837 package tests passed, 19 optional skips, plus the real Chromium flow; typechecking, lint and build passed. Review judgments remain fallible and do not establish independent factual verification.

The attached artifact is identical to the package submitted to npm as @absolutejs/rag@0.19.0 (SHA-1 82c52d453247ead4fb9c38306bbb01eab5f68c33). It provides a reproducible download while the registry version is unavailable.