fix(review): upgrade old default items of anchored files, tag anchored results (#390)

A pending default item recorded before the saver anchor no longer
shortcuts the rescan when only the anchor resolves the file: the
anchored item supersedes it. Apply accepts a resolved re-resolution only
when it is tagged as the saver anchor's, the anchored pair must carry a
positive text to choose, and limited anchored evidence still counts as a
choice. TESTING.md describes the ruling.

database/review_schema.py

@@ -229,14 +229,14 @@ def evidence_offers_choice(evidence: Any) -> bool:
     """
     if not isinstance(evidence, dict):
         return False
+    # The saver anchor's one pair (#390) is a suggestion to confirm.
+    needed = 1 if evidence.get("anchor") == "saver" else MIN_CHOOSABLE
     if evidence.get("limited"):
         total = evidence.get("candidate_total")
-        return type(total) is int and total >= MIN_CHOOSABLE
+        return type(total) is int and total >= needed
     candidates = evidence.get("candidates")
     if not isinstance(candidates, list):
         return False
-    # The saver anchor's one pair (#390) is a suggestion to confirm.
-    needed = 1 if evidence.get("anchor") == "saver" else MIN_CHOOSABLE
     return sum(1 for c in candidates if choosable(c)) >= needed