feat(family): the shape ledger judges against family ideas, across languages (milestone 463 step 5, #4991)

- classify_shapes takes idea_id: the shape is judged against the idea's
  reference in its language, or its first.
- A shape classified against a canon idea's reference moves the project's
  adoption row (instance -> adopted, variant -> variant). Withdrawing the
  shapes that gave an answer returns it to unassessed. This runs on
  classify_shapes, the sweep, confirm_proposals and the coverage refresh.
- assess and undo refuse an answer the shapes contradict. A conflict
  resolution re-judges the variant shapes on both sides.
- The proposer's family arm offers a canon idea's reference on a shared
  platform, in any language. It proposes only when the reference is the top
  hit over every readable snippet and scores at least 0.70. The pairs this
  was measured on are recorded beside _FAMILY_FLOOR. The proposer is now v6.
- The matrix cell shows the code that answers it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/mcp/tools/family.py

@@ -280,6 +280,12 @@ async def assess_family_adoption(
     variant cancels it, owed again reopens it. The same answer given twice
     records nothing the second time.
 
+    When the project's code is in the shape ledger, prefer answering THERE:
+    classify_shapes the shape against the idea (idea_id=…) as an instance or
+    a variant, and this answer moves with it. An answer the shapes already
+    give otherwise is refused — the two ledgers never disagree; reclassify
+    the shapes if they are wrong.
+
     Args:
         project_id: the project answering.
         idea_id: the canon idea.