feat(ledger): divergence readout — button B where button A is canon, shape history, and judged-shape recheck (#2793, milestone 294 step 7)

Every judgment now goes through one helper that remembers the fingerprint
judged (classified_sha) and writes a code_shape_events row; the sync writes
vanished / reappeared / drifted events and flags recheck_at when a body
moves under an instance/variant. The refresh flags diverges_from on shapes
new since the previous computation that sit where one canon dominates the
judged siblings of their directory+kind and were not proposed as that canon
(a first seed flags nothing); the write-path hint asks the same question
in-band for the shapes the hook names. list_shapes(flag=divergence|recheck),
shape_history(project_id, path, symbol) (read-only), coverage line/payload/
card carry divergent + recheck. Backup v8 carries the history. Plugin 0.1.36.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_write_path_trigger.py

@@ -1248,3 +1248,42 @@ def test_hook_sends_the_enclosing_definition_for_a_body_edit(tmp_path):
         },
     })
     assert seen["shapes"] == ["sym:onTrash"]
+
+
+@pytest.mark.asyncio
+async def test_the_write_time_divergence_check_is_named_in_band():
+    """#2793: the hook named a shape at a path whose directory a canon
+    dominates, and the stamp didn't make it that canon's instance — the hint
+    must say so at the write, even when nothing else renders."""
+    from scribe.services import plugin_context as pc
+    div = [{"symbol": "confirmDanger", "kind": "sym", "canon_snippet_id": 2761,
+            "instances": 20, "judged": 21}]
+    check = AsyncMock(return_value=div)
+    with patch.object(pc, "get_writepath_config", AsyncMock(return_value=_cfg())), \
+         patch.object(pc.snippets_svc, "list_snippets", AsyncMock(return_value=([], 0))), \
+         patch.object(pc, "semantic_search_notes", AsyncMock(return_value=[])), \
+         patch.object(pc, "record_retrieval", MagicMock()), \
+         patch.object(pc, "owner_names_for", AsyncMock(return_value={})), \
+         patch.object(pc.shape_ledger_svc, "recent_pulls", AsyncMock(return_value={})), \
+         patch.object(pc.shape_ledger_svc, "write_time_divergence", check):
+        out = await pc.build_write_path_hint(
+            1, "frontend/src/components/Danger.vue", code=REAL_CODE, project_id=24,
+            stamp_shapes=[("sym", "confirmDanger")],
+        )
+    check.assert_awaited_once_with(24, "frontend/src/components/Danger.vue",
+                                   [("sym", "confirmDanger")], [])
+    assert out["divergence"] == div
+    assert "Divergence check at `frontend/src/components/Danger.vue`" in out["context"]
+    assert "`confirmDanger` → #2761 (20 of 21 judged siblings are its instances)" in out["context"]
+    assert "variant" in out["context"]
+    # No project → no check at all.
+    check.reset_mock()
+    with patch.object(pc, "get_writepath_config", AsyncMock(return_value=_cfg())), \
+         patch.object(pc.snippets_svc, "list_snippets", AsyncMock(return_value=([], 0))), \
+         patch.object(pc, "semantic_search_notes", AsyncMock(return_value=[])), \
+         patch.object(pc, "record_retrieval", MagicMock()), \
+         patch.object(pc.shape_ledger_svc, "recent_pulls", AsyncMock(return_value={})), \
+         patch.object(pc.shape_ledger_svc, "write_time_divergence", check):
+        out = await pc.build_write_path_hint(1, "x.py", code=REAL_CODE, stamp_shapes=[("sym", "f")])
+    check.assert_not_awaited()
+    assert out["divergence"] == []